diff --git a/requirements/common.txt b/requirements/common.txt
index ad92ba3ad..1058ab91a 100644
--- a/requirements/common.txt
+++ b/requirements/common.txt
@@ -30,7 +30,7 @@ filelock >= 3.16.1 # need to contain https://github.com/tox-dev/filelock/pull/31
 partial-json-parser # used for parsing partial JSON outputs
 pyzmq >= 25.0.0
 msgspec
-gguf >= 0.13.0
+gguf >= 0.17.0
 mistral_common[image] >= 1.8.5
 opencv-python-headless >= 4.11.0    # required for video IO
 pyyaml
diff --git a/tests/models/multimodal/generation/test_multimodal_gguf.py b/tests/models/multimodal/generation/test_multimodal_gguf.py
new file mode 100644
index 000000000..e596b20c6
--- /dev/null
+++ b/tests/models/multimodal/generation/test_multimodal_gguf.py
@@ -0,0 +1,115 @@
+# SPDX-License-Identifier: Apache-2.0
+# SPDX-FileCopyrightText: Copyright contributors to the vLLM project
+
+from typing import Literal, NamedTuple
+
+import pytest
+from huggingface_hub import hf_hub_download
+from pytest import MarkDecorator
+
+from tests.quantization.utils import is_quant_method_supported
+from vllm.assets.image import ImageAsset
+from vllm.utils.torch_utils import set_default_torch_num_threads
+
+from ....conftest import PromptImageInput, VllmRunner
+from ...utils import check_logprobs_close
+
+
+class GGUFMMTestConfig(NamedTuple):
+    original_model: str
+    gguf_repo: str
+    gguf_backbone: str
+    gguf_mmproj: str
+    prompt: list[str]
+    mm_data: dict[Literal["images"], PromptImageInput]
+    max_model_len: int = 4096
+    marks: list[MarkDecorator] = []
+
+    @property
+    def gguf_model(self):
+        hf_hub_download(self.gguf_repo, filename=self.gguf_mmproj)
+        return hf_hub_download(self.gguf_repo, filename=self.gguf_backbone)
+
+
+GEMMA3_CONFIG = GGUFMMTestConfig(
+    original_model="google/gemma-3-4b-it",
+    gguf_repo="google/gemma-3-4b-it-qat-q4_0-gguf",
+    gguf_backbone="gemma-3-4b-it-q4_0.gguf",
+    gguf_mmproj="mmproj-model-f16-4B.gguf",
+    prompt=["<start_of_image>Describe this image in detail:"],
+    mm_data={"images": [ImageAsset("stop_sign").pil_image]},
+    marks=[pytest.mark.core_model],
+)
+
+MODELS_TO_TEST = [GEMMA3_CONFIG]
+
+
+def run_multimodal_gguf_test(
+    vllm_runner: type[VllmRunner],
+    model: GGUFMMTestConfig,
+    dtype: str,
+    max_tokens: int,
+    num_logprobs: int,
+):
+    # Run gguf model.
+    with (
+        set_default_torch_num_threads(1),
+        vllm_runner(
+            model_name=model.gguf_model,
+            enforce_eager=True,
+            tokenizer_name=model.original_model,
+            dtype=dtype,
+            max_model_len=model.max_model_len,
+        ) as gguf_model,
+    ):
+        gguf_outputs = gguf_model.generate_greedy_logprobs(
+            prompts=model.prompt,
+            max_tokens=max_tokens,
+            num_logprobs=num_logprobs,
+            **model.mm_data,
+        )
+
+    # Run unquantized model.
+    with vllm_runner(
+        model_name=model.original_model,
+        enforce_eager=True,  # faster tests
+        dtype=dtype,
+        max_model_len=model.max_model_len,
+    ) as original_model:
+        original_outputs = original_model.generate_greedy_logprobs(
+            prompts=model.prompt,
+            max_tokens=max_tokens,
+            num_logprobs=num_logprobs,
+            **model.mm_data,
+        )
+
+    check_logprobs_close(
+        outputs_0_lst=original_outputs,
+        outputs_1_lst=gguf_outputs,
+        name_0="original",
+        name_1="gguf",
+    )
+
+
+@pytest.mark.skipif(
+    not is_quant_method_supported("gguf"),
+    reason="gguf is not supported on this GPU type.",
+)
+@pytest.mark.parametrize(
+    "model",
+    [
+        pytest.param(test_config, marks=test_config.marks)
+        for test_config in MODELS_TO_TEST
+    ],
+)
+@pytest.mark.parametrize("dtype", ["bfloat16"])
+@pytest.mark.parametrize("max_tokens", [32])
+@pytest.mark.parametrize("num_logprobs", [10])
+def test_models(
+    vllm_runner: type[VllmRunner],
+    model: GGUFMMTestConfig,
+    dtype: str,
+    max_tokens: int,
+    num_logprobs: int,
+) -> None:
+    run_multimodal_gguf_test(vllm_runner, model, dtype, max_tokens, num_logprobs)
diff --git a/tests/models/quantization/test_gguf.py b/tests/models/quantization/test_gguf.py
index 5e2438857..3b9597507 100644
--- a/tests/models/quantization/test_gguf.py
+++ b/tests/models/quantization/test_gguf.py
@@ -78,6 +78,12 @@ DOLPHIN_CONFIG = GGUFTestConfig(
     gguf_filename="tinydolphin-2.8-1.1b.Q6_K.gguf",
 )
 
+GEMMA3_CONFIG = GGUFTestConfig(
+    original_model="google/gemma-3-270m-it",
+    gguf_repo="ggml-org/gemma-3-270m-it-qat-GGUF",
+    gguf_filename="gemma-3-270m-it-qat-Q4_0.gguf",
+)
+
 MODELS = [
     # LLAMA_CONFIG, # broken: https://github.com/vllm-project/vllm/issues/19458
     QWEN2_CONFIG,
@@ -85,6 +91,7 @@ MODELS = [
     GPT2_CONFIG,
     STABLELM_CONFIG,
     DOLPHIN_CONFIG,
+    GEMMA3_CONFIG,
     # STARCODER_CONFIG, # broken
 ]
 
@@ -148,7 +155,7 @@ def check_model_outputs(
     "model",
     [pytest.param(test_config, marks=test_config.marks) for test_config in MODELS],
 )
-@pytest.mark.parametrize("dtype", ["half"])
+@pytest.mark.parametrize("dtype", ["bfloat16"])
 @pytest.mark.parametrize("max_tokens", [32])
 @pytest.mark.parametrize("num_logprobs", [5])
 @pytest.mark.parametrize("tp_size", [1])
diff --git a/vllm/config/model.py b/vllm/config/model.py
index b3a28af6d..49fe0bcd9 100644
--- a/vllm/config/model.py
+++ b/vllm/config/model.py
@@ -33,10 +33,14 @@ from vllm.transformers_utils.config import (
     try_get_generation_config,
     try_get_safetensors_metadata,
     try_get_tokenizer_config,
+    uses_custom_attention_masks,
     uses_mrope,
 )
+from vllm.transformers_utils.gguf_utils import (
+    maybe_patch_hf_config_from_gguf,
+)
 from vllm.transformers_utils.runai_utils import ObjectStorageModel, is_runai_obj_uri
-from vllm.transformers_utils.utils import maybe_model_redirect
+from vllm.transformers_utils.utils import check_gguf_file, maybe_model_redirect
 from vllm.utils.import_utils import LazyLoader
 from vllm.utils.torch_utils import common_broadcastable_dtype
 
@@ -450,6 +454,12 @@ class ModelConfig:
         self.model = maybe_model_redirect(self.model)
         # The tokenizer is consistent with the model by default.
         if self.tokenizer is None:
+            if check_gguf_file(self.model):
+                raise ValueError(
+                    "Using a tokenizer is mandatory when loading a GGUF model. "
+                    "Please specify the tokenizer path or name using the "
+                    "--tokenizer argument."
+                )
             self.tokenizer = self.model
         if self.tokenizer_revision is None:
             self.tokenizer_revision = self.revision
@@ -508,6 +518,10 @@ class ModelConfig:
             hf_overrides_kw=hf_overrides_kw,
             hf_overrides_fn=hf_overrides_fn,
         )
+        hf_config = maybe_patch_hf_config_from_gguf(
+            self.model,
+            hf_config,
+        )
 
         self.hf_config = hf_config
         if dict_overrides:
@@ -1605,6 +1619,10 @@ class ModelConfig:
     def uses_mrope(self) -> bool:
         return uses_mrope(self.hf_config)
 
+    @property
+    def uses_custom_attention_masks(self) -> bool:
+        return uses_custom_attention_masks(self.hf_config)
+
     @property
     def is_multimodal_model(self) -> bool:
         return self.multimodal_config is not None
diff --git a/vllm/model_executor/layers/quantization/gguf.py b/vllm/model_executor/layers/quantization/gguf.py
index caabcd0ca..42d7a6737 100644
--- a/vllm/model_executor/layers/quantization/gguf.py
+++ b/vllm/model_executor/layers/quantization/gguf.py
@@ -1,7 +1,8 @@
 # SPDX-License-Identifier: Apache-2.0
 # SPDX-FileCopyrightText: Copyright contributors to the vLLM project
 
-from collections.abc import Callable
+from collections.abc import Callable, Mapping
+from types import MappingProxyType
 from typing import Any, Optional
 
 import gguf
@@ -26,7 +27,11 @@ from vllm.model_executor.layers.quantization.base_config import (
     QuantizationConfig,
     QuantizeMethodBase,
 )
-from vllm.model_executor.layers.vocab_parallel_embedding import VocabParallelEmbedding
+from vllm.model_executor.layers.vocab_parallel_embedding import (
+    UnquantizedEmbeddingMethod,
+    VocabParallelEmbedding,
+)
+from vllm.model_executor.models.utils import WeightsMapper
 from vllm.model_executor.utils import set_weight_attrs
 from vllm.utils.torch_utils import direct_register_custom_op
 
@@ -65,18 +70,70 @@ class GGUFConfig(QuantizationConfig):
         self, layer: torch.nn.Module, prefix: str
     ) -> Optional["QuantizeMethodBase"]:
         if isinstance(layer, LinearBase):
-            if is_layer_skipped_gguf(prefix, self.unquantized_modules):
+            if is_layer_skipped_gguf(
+                prefix, self.unquantized_modules, self.packed_modules_mapping
+            ):
                 return UnquantizedLinearMethod()
             return GGUFLinearMethod(self)
         elif isinstance(layer, VocabParallelEmbedding):
+            if is_layer_skipped_gguf(
+                prefix, self.unquantized_modules, self.packed_modules_mapping
+            ):
+                return UnquantizedEmbeddingMethod()
             return GGUFEmbeddingMethod(self)
         elif isinstance(layer, FusedMoE):
             return GGUFMoEMethod(self, layer.moe_config)
         return None
 
+    def apply_vllm_mapper(self, hf_to_vllm_mapper: "WeightsMapper"):
+        """
+        Interface for models to update module names referenced in
+        quantization configs in order to reflect the vllm model structure
 
-def is_layer_skipped_gguf(prefix: str, unquantized_modules: list[str]):
-    return any(module_name in prefix for module_name in unquantized_modules)
+        :param hf_to_vllm_mapper: maps from hf model structure (the assumed
+            structure of the qconfig) to vllm model structure
+        """
+        if self.unquantized_modules is not None:
+            self.unquantized_modules = hf_to_vllm_mapper.apply_list(
+                self.unquantized_modules
+            )
+
+
+def is_layer_skipped_gguf(
+    prefix: str,
+    unquantized_modules: list[str],
+    fused_mapping: Mapping[str, list[str]] = MappingProxyType({}),
+):
+    # Fused layers like gate_up_proj or qkv_proj will not be fused
+    # in the safetensors checkpoint. So, we convert the name
+    # from the fused version to unfused + check to make sure that
+    # each shard of the fused layer has the same scheme.
+    proj_name = prefix.split(".")[-1]
+    if proj_name in fused_mapping:
+        shard_prefixes = [
+            prefix.replace(proj_name, shard_proj_name)
+            for shard_proj_name in fused_mapping[proj_name]
+        ]
+
+        is_skipped = None
+        for shard_prefix in shard_prefixes:
+            is_shard_skipped = any(
+                shard_prefix in module_name for module_name in unquantized_modules
+            )
+
+            if is_skipped is None:
+                is_skipped = is_shard_skipped
+            elif is_shard_skipped != is_skipped:
+                raise ValueError(
+                    f"Detected some but not all shards of {prefix} "
+                    "are quantized. All shards of fused layers "
+                    "to have the same precision."
+                )
+    else:
+        is_skipped = any(module_name in prefix for module_name in unquantized_modules)
+
+    assert is_skipped is not None
+    return is_skipped
 
 
 UNQUANTIZED_TYPES = {WeightType.F32, WeightType.F16, WeightType.BF16}
diff --git a/vllm/model_executor/model_loader/gguf_loader.py b/vllm/model_executor/model_loader/gguf_loader.py
index 7db1fc167..2416836be 100644
--- a/vllm/model_executor/model_loader/gguf_loader.py
+++ b/vllm/model_executor/model_loader/gguf_loader.py
@@ -7,10 +7,11 @@ import gguf
 import torch
 import torch.nn as nn
 from huggingface_hub import hf_hub_download
-from transformers import AutoModelForCausalLM
+from transformers import AutoModelForCausalLM, AutoModelForImageTextToText
 
 from vllm.config import ModelConfig, VllmConfig
 from vllm.config.load import LoadConfig
+from vllm.logger import init_logger
 from vllm.model_executor.model_loader.base_loader import BaseModelLoader
 from vllm.model_executor.model_loader.utils import (
     initialize_model,
@@ -21,8 +22,11 @@ from vllm.model_executor.model_loader.weight_utils import (
     get_gguf_weight_type_map,
     gguf_quant_weights_iterator,
 )
+from vllm.transformers_utils.gguf_utils import detect_gguf_multimodal
 from vllm.utils.torch_utils import set_default_torch_dtype
 
+logger = init_logger(__name__)
+
 
 class GGUFModelLoader(BaseModelLoader):
     """
@@ -67,7 +71,15 @@ class GGUFModelLoader(BaseModelLoader):
         https://github.com/ggerganov/ggml/blob/master/docs/gguf.md for details.
         """
         config = model_config.hf_config
+        # Get text config to handle both nested (multimodal) and flat
+        # (text-only) config structures. For multimodal models like
+        # Gemma3Config, this returns config.text_config. For text-only
+        # models, this returns config itself.
+        text_config = config.get_text_config()
         model_type = config.model_type
+        is_multimodal = (
+            hasattr(config, "vision_config") and config.vision_config is not None
+        )
         gguf_to_hf_name_map = {}
         # hack: ggufs have a different name than transformers
         if model_type == "cohere":
@@ -115,24 +127,167 @@ class GGUFModelLoader(BaseModelLoader):
                 break
         if arch is None:
             raise RuntimeError(f"Unknown gguf model_type: {model_type}")
-        num_layers = config.num_hidden_layers
-        name_map = gguf.get_tensor_name_map(arch, num_layers)
+        text_num_layers = text_config.num_hidden_layers
+        text_name_map = gguf.get_tensor_name_map(arch, text_num_layers)
+
+        if is_multimodal:
+            mm_proj_arch = gguf.MODEL_ARCH.MMPROJ
+            vision_num_layers = config.vision_config.num_hidden_layers
+            vision_name_map = gguf.get_tensor_name_map(mm_proj_arch, vision_num_layers)
+        else:
+            vision_name_map = None
+
+        # Create dummy model to extract parameter names
+        # For multimodal: use AutoModelForImageTextToText to get
+        # language + vision + projector params
+        # For text-only: use AutoModelForCausalLM to get language model params
+        auto_cls = (
+            AutoModelForImageTextToText if is_multimodal else AutoModelForCausalLM
+        )
         with torch.device("meta"):
-            dummy_model = AutoModelForCausalLM.from_config(
+            dummy_model = auto_cls.from_config(
                 config, trust_remote_code=model_config.trust_remote_code
             )
-        state_dict = dummy_model.state_dict()
 
+        state_dict = dummy_model.state_dict()
+        if hf_checkpoint_map := getattr(
+            dummy_model, "_checkpoint_conversion_mapping", None
+        ):
+
+            def revert_hf_rename(name: str) -> str:
+                for original_name, hf_name in hf_checkpoint_map.items():
+                    if hf_name in name:
+                        name = name.replace(hf_name, original_name).lstrip("^")
+                return name
+
+            state_dict = {
+                revert_hf_rename(name): tensor for name, tensor in state_dict.items()
+            }
+
+        def find_hf_name_in_tensor_map(hf_name: str) -> str | None:
+            """
+            Map HuggingFace parameter name to GGUF tensor name.
+
+            This function handles the mismatch between HF parameter naming
+            conventions and gguf-py's expected format:
+            1. Strips 'model.' prefix (common in multimodal models)
+            2. Converts '_weight' suffix to '.weight' (Gemma3 compatibility)
+            3. Searches vision_name_map for multimodal parameters
+            4. Falls back to text_name_map for language model parameters
+
+            Args:
+                hf_name: Full HuggingFace parameter name (e.g.,
+                        'model.multi_modal_projector.mm_soft_emb_norm.weight')
+
+            Returns:
+                GGUF tensor name with suffix (e.g., 'mm.soft_emb_norm.weight')
+                or None if no mapping found
+            """
+            # Strip 'language_model.' prefix for multimodal models - gguf-py
+            # tensor mappings expect parameter names without this prefix.
+            # Note: 'model.' prefix should be KEPT for text-only models as
+            # gguf-py expects it.
+            if hf_name.startswith("language_model."):
+                hf_name = hf_name[15:]  # Remove 'language_model.'
+
+            # Parse parameter name and suffix
+            if hf_name.endswith((".weight", ".bias")):
+                base_name, suffix = hf_name.rsplit(".", 1)
+            else:
+                base_name, suffix = hf_name, ""
+                # Handle '_weight' suffix (Gemma3 naming: parameter ends with
+                # '_weight' instead of '.weight')
+                if base_name.endswith("_weight"):
+                    base_name = base_name[:-7]  # Remove '_weight'
+                    suffix = "weight"
+
+            gguf_name = None
+            # Priority 1: Search vision/projector parameters for multimodal models
+            if vision_name_map is not None:
+                gguf_name = vision_name_map.get_name(base_name)
+
+            # Priority 2: Search text backbone parameters
+            if gguf_name is None:
+                gguf_name = text_name_map.get_name(base_name)
+
+            if gguf_name is None:
+                return None
+
+            return gguf_name + "." + suffix
+
+        # Build mapping and track unmapped parameters
+        unmapped_params = []
         for hf_name in state_dict:
-            name, suffix = hf_name.rsplit(".", 1)
-            gguf_name = name_map.get_name(name)
-            gguf_to_hf_name_map[f"{gguf_name}.{suffix}"] = hf_name
+            gguf_name_with_suffix = find_hf_name_in_tensor_map(hf_name)
+
+            # Track mapping success
+            if gguf_name_with_suffix is not None:
+                gguf_to_hf_name_map[gguf_name_with_suffix] = hf_name
+                logger.debug("Mapped GGUF %s → HF %s", gguf_name_with_suffix, hf_name)
+            elif hf_name not in gguf_to_hf_name_map.values():
+                # Parameter not in manual overrides either
+                unmapped_params.append(hf_name)
+
+        # All parameters must be mapped: both vision/projector and backbone
+        if unmapped_params:
+            raise RuntimeError(
+                f"Failed to map GGUF parameters "
+                f"({len(unmapped_params)}): "
+                f"{unmapped_params}"
+            )
         return gguf_to_hf_name_map
 
+    def _get_gguf_weight_type(
+        self,
+        model_config: ModelConfig,
+        model_name_or_path: str,
+        gguf_to_hf_name_map: dict[str, str],
+    ) -> dict[str, str]:
+        weight_type_map = get_gguf_weight_type_map(
+            model_config.model, gguf_to_hf_name_map
+        )
+        is_multimodal = hasattr(model_config.hf_config, "vision_config")
+        if is_multimodal:
+            mmproj_file = detect_gguf_multimodal(model_name_or_path)
+            assert mmproj_file is not None, (
+                "Could not find mm_proj file for multimodal GGUF model"
+            )
+            logger.info("Loading extra mm_proj weights from %s...", mmproj_file)
+            mm_proj_weight_type_map = get_gguf_weight_type_map(
+                mmproj_file, gguf_to_hf_name_map
+            )
+            weight_type_map.update(mm_proj_weight_type_map)
+        return weight_type_map
+
     def _get_weights_iterator(
-        self, model_name_or_path: str, gguf_to_hf_name_map: dict[str, str]
+        self,
+        model_config: ModelConfig,
+        model_name_or_path: str,
+        gguf_to_hf_name_map: dict[str, str],
     ) -> Generator[tuple[str, torch.Tensor], None, None]:
-        return gguf_quant_weights_iterator(model_name_or_path, gguf_to_hf_name_map)
+        """
+        Iterate over GGUF model weights, loading from both main model file and
+        mmproj.gguf for multimodal Gemma3 models.
+
+        For Gemma3 multimodal GGUF models:
+        - Main file (gemma-3-*.gguf): Language model weights (model.*)
+        - mmproj file (mmproj*.gguf): Vision tower + projector weights (v.*, mm.*)
+
+        Yields:
+            Tuples of (parameter_name, tensor) for all model weights
+        """
+        hf_config = model_config.hf_config
+        is_multimodal = hasattr(hf_config, "vision_config")
+
+        if is_multimodal:
+            # Load mm_proj (mm_encoder + projector) for multimodal weights
+            mmproj_file = detect_gguf_multimodal(model_name_or_path)
+            assert mmproj_file is not None, (
+                "Could not find mm_proj file for multimodal GGUF model"
+            )
+            yield from gguf_quant_weights_iterator(mmproj_file, gguf_to_hf_name_map)
+
+        yield from gguf_quant_weights_iterator(model_name_or_path, gguf_to_hf_name_map)
 
     def download_model(self, model_config: ModelConfig) -> None:
         self._prepare_weights(model_config.model)
@@ -141,7 +296,7 @@ class GGUFModelLoader(BaseModelLoader):
         local_model_path = self._prepare_weights(model_config.model)
         gguf_weights_map = self._get_gguf_weights_map(model_config)
         model.load_weights(
-            self._get_weights_iterator(local_model_path, gguf_weights_map)
+            self._get_weights_iterator(model_config, local_model_path, gguf_weights_map)
         )
 
     def load_model(
@@ -156,14 +311,19 @@ class GGUFModelLoader(BaseModelLoader):
         ):
             model_config.hf_config.update({"tie_word_embeddings": True})
 
-        weight_type_map = get_gguf_weight_type_map(model_config.model, gguf_weights_map)
-
+        weight_type_map = self._get_gguf_weight_type(
+            model_config, local_model_path, gguf_weights_map
+        )
         # filter out unquantized modules to skip
         unquant_names = [
             name.removesuffix(".weight")
             for name, weight_type in weight_type_map.items()
-            if weight_type == "F32" and name.endswith(".weight")
+            if weight_type in ("F32", "F16", "BF16") and name.endswith(".weight")
         ]
+        logger.debug(
+            "GGUF unquantized modules: %s",
+            unquant_names,
+        )
         vllm_config.quant_config.unquantized_modules.extend(unquant_names)
 
         target_device = torch.device(device_config.device)
diff --git a/vllm/model_executor/model_loader/weight_utils.py b/vllm/model_executor/model_loader/weight_utils.py
index 93986e5f2..89634cbf4 100644
--- a/vllm/model_executor/model_loader/weight_utils.py
+++ b/vllm/model_executor/model_loader/weight_utils.py
@@ -836,7 +836,11 @@ def gguf_quant_weights_iterator(
 ) -> Generator[tuple[str, torch.Tensor], None, None]:
     """
     Iterate over the quant weights in the model gguf files and convert
-    them to torch tensors
+    them to torch tensors.
+    Be careful of the order of yielding weight types and weights data,
+    we have to yield all weight types first before yielding any weights.
+    Otherwise it would cause issue when loading weights with for packed
+    layer with different quant types.
     """
 
     reader = gguf.GGUFReader(gguf_file)
@@ -846,7 +850,7 @@ def gguf_quant_weights_iterator(
             weight_type = tensor.tensor_type
             name = gguf_to_hf_name_map[tensor.name]
 
-            if weight_type.name != "F32":
+            if weight_type.name not in ("F32", "BF16", "F16"):
                 weight_type_name = name.replace("weight", "qweight_type")
                 weight_type = torch.tensor(weight_type)
                 yield weight_type_name, weight_type
@@ -856,7 +860,7 @@ def gguf_quant_weights_iterator(
             weight = tensor.data
             weight_type = tensor.tensor_type
             name = gguf_to_hf_name_map[tensor.name]
-            if weight_type.name != "F32":
+            if weight_type.name not in ("F32", "BF16", "F16"):
                 name = name.replace("weight", "qweight")
             param = torch.tensor(weight)
             yield name, param
diff --git a/vllm/model_executor/models/gemma3_mm.py b/vllm/model_executor/models/gemma3_mm.py
index 8e2bbe8f7..fe83c8b63 100644
--- a/vllm/model_executor/models/gemma3_mm.py
+++ b/vllm/model_executor/models/gemma3_mm.py
@@ -2,7 +2,7 @@
 # SPDX-FileCopyrightText: Copyright contributors to the vLLM project
 import math
 from collections.abc import Iterable, Mapping, Sequence
-from typing import Annotated, Any, Literal, TypeAlias
+from typing import Annotated, Any, Literal
 
 import torch
 from torch import nn
@@ -20,12 +20,7 @@ from vllm.multimodal.inputs import (
     MultiModalFieldConfig,
     MultiModalKwargsItems,
 )
-from vllm.multimodal.parse import (
-    ImageEmbeddingItems,
-    ImageProcessorItems,
-    ImageSize,
-    MultiModalDataItems,
-)
+from vllm.multimodal.parse import ImageProcessorItems, ImageSize, MultiModalDataItems
 from vllm.multimodal.processing import (
     BaseMultiModalProcessor,
     BaseProcessingInfo,
@@ -76,15 +71,7 @@ class Gemma3ImagePixelInputs(TensorSchema):
     num_patches: Annotated[torch.Tensor, TensorShape("bn")]
 
 
-class Gemma3ImageEmbeddingInputs(TensorSchema):
-    type: Literal["image_embeds"] = "image_embeds"
-    image_embeds: Annotated[
-        torch.Tensor,
-        TensorShape("ni", "nf", "hs"),
-    ]
-
-
-Gemma3ImageInputs: TypeAlias = Gemma3ImagePixelInputs | Gemma3ImageEmbeddingInputs
+Gemma3ImageInputs = Gemma3ImagePixelInputs
 
 
 class Gemma3ProcessingInfo(BaseProcessingInfo):
@@ -191,9 +178,8 @@ class Gemma3ProcessingInfo(BaseProcessingInfo):
     def get_image_repl(
         self,
         *,
-        image_width: int | None,
-        image_height: int | None,
-        num_crops: int | None = None,
+        image_width: int,
+        image_height: int,
         processor: Gemma3Processor | None,
     ) -> PromptUpdateDetails[str]:
         if processor is None:
@@ -201,13 +187,11 @@ class Gemma3ProcessingInfo(BaseProcessingInfo):
 
         boi_token = processor.boi_token
 
-        if num_crops is None:
-            assert image_width is not None and image_height is not None
-            num_crops = self.get_num_crops(
-                image_width=image_width,
-                image_height=image_height,
-                processor=processor,
-            )
+        num_crops = self.get_num_crops(
+            image_width=image_width,
+            image_height=image_height,
+            processor=processor,
+        )
 
         if num_crops == 0:
             image_text = boi_token
@@ -337,7 +321,6 @@ class Gemma3MultiModalProcessor(BaseMultiModalProcessor[Gemma3ProcessingInfo]):
         return dict(
             pixel_values=MultiModalFieldConfig.flat_from_sizes("image", num_patches),
             num_patches=MultiModalFieldConfig.batched("image"),
-            image_embeds=MultiModalFieldConfig.batched("image"),
         )
 
     def _get_prompt_updates(
@@ -350,19 +333,7 @@ class Gemma3MultiModalProcessor(BaseMultiModalProcessor[Gemma3ProcessingInfo]):
         image_token = hf_processor.boi_token
 
         def get_replacement_gemma3(item_idx: int):
-            images = mm_items.get_items(
-                "image", (ImageEmbeddingItems, ImageProcessorItems)
-            )
-
-            if isinstance(images, ImageEmbeddingItems):
-                # For image embedding inputs, only support no crops cases
-                # since it's not supported in hf processor anyway
-                return self.info.get_image_repl(
-                    image_width=None,
-                    image_height=None,
-                    num_crops=0,
-                    processor=hf_processor,
-                )
+            images = mm_items.get_items("image", ImageProcessorItems)
 
             image_size = images.get_image_size(item_idx)
             return self.info.get_image_repl(
@@ -586,19 +557,17 @@ class Gemma3ForConditionalGeneration(
         pixel_values = kwargs.pop("pixel_values", None)
         num_patches = kwargs.pop("num_patches", None)
         image_embeds = kwargs.pop("image_embeds", None)
+        assert image_embeds is None, "Gemma3 does not support image_embeds."
+        if pixel_values is None:
+            return None
 
-        if pixel_values is not None:
-            image_size = self.config.vision_config.image_size
-            return Gemma3ImagePixelInputs(
-                pixel_values=pixel_values,
-                num_patches=num_patches,
-                resolve_bindings={"h": image_size, "w": image_size},
-            )
-        elif image_embeds is not None:
-            return Gemma3ImageEmbeddingInputs(
-                image_embeds=image_embeds,
-                type="image_embeds",
-            )
+        image_size = self.config.vision_config.image_size
+
+        return Gemma3ImagePixelInputs(
+            pixel_values=pixel_values,
+            num_patches=num_patches,
+            resolve_bindings={"h": image_size, "w": image_size},
+        )
 
     def _image_pixels_to_features(
         self,
@@ -610,9 +579,7 @@ class Gemma3ForConditionalGeneration(
     def _process_image_input(
         self,
         image_input: Gemma3ImageInputs,
-    ) -> torch.Tensor | list[torch.Tensor]:
-        if image_input["type"] == "image_embeds":
-            return image_input["image_embeds"]
+    ) -> list[torch.Tensor]:
         assert self.vision_tower is not None
 
         pixel_values = image_input["pixel_values"]
@@ -629,13 +596,33 @@ class Gemma3ForConditionalGeneration(
     def get_language_model(self) -> torch.nn.Module:
         return self.language_model
 
-    def embed_multimodal(self, **kwargs: object) -> MultiModalEmbeddings:
+    def get_multimodal_embeddings(self, **kwargs: object) -> MultiModalEmbeddings:
         image_input = self._parse_and_validate_image_input(**kwargs)
         if image_input is None:
             return []
 
         return self._process_image_input(image_input)
 
+    def embed_input_ids(
+        self,
+        input_ids: torch.Tensor,
+        multimodal_embeddings: MultiModalEmbeddings | None = None,
+        *,
+        is_multimodal: torch.Tensor | None = None,
+        handle_oov_mm_token: bool = True,
+    ) -> torch.Tensor:
+        # Early return for text-only inference (no multimodal data)
+        if multimodal_embeddings is None or is_multimodal is None:
+            return super().embed_input_ids(input_ids)
+
+        # Use interface default with OOV handling enabled
+        return super().embed_input_ids(
+            input_ids,
+            multimodal_embeddings=multimodal_embeddings,
+            is_multimodal=is_multimodal,
+            handle_oov_mm_token=handle_oov_mm_token,
+        )
+
     def forward(
         self,
         input_ids: torch.Tensor,
@@ -657,6 +644,79 @@ class Gemma3ForConditionalGeneration(
 
         return hidden_states
 
+    def generate_attention_masks(
+        self,
+        input_ids: torch.Tensor,
+        positions: torch.Tensor,
+        mask_dtype: torch.dtype,
+    ) -> dict[str, Any]:
+        """Generate custom attention masks for Gemma3 multimodal inputs.
+
+        This is called by V1 engine's gpu_model_runner during preprocessing
+        to generate attention masks that allow bidirectional attention between
+        image tokens while maintaining causal attention for text.
+        """
+        # NOTE(woosuk): Here, we distinguish the sequences by the position id 0.
+        # This is a HACK. Fix this.
+        start_indices = (positions == 0).cpu().nonzero()
+        num_seqs = len(start_indices)
+        seq_lens = []
+        for i in range(num_seqs):
+            start_idx = start_indices[i]
+            end_idx = start_indices[i + 1] if i < num_seqs - 1 else len(input_ids)
+            seq_lens.append(end_idx - start_idx)
+
+        global_attn_masks = []
+        local_attn_masks = []
+        start_idx = 0
+        for seq_idx, seq_len in enumerate(seq_lens):
+            end_idx = start_idx + seq_len
+            input_token_ids = input_ids[start_idx:end_idx]
+
+            # Find image token positions
+            img_pos = input_token_ids == self.config.image_token_index
+
+            start_idx = end_idx
+
+            # Create a global causal mask
+            global_attn_mask = torch.empty(
+                1,
+                1,
+                seq_len,
+                seq_len,
+                dtype=mask_dtype,
+                device=input_ids.device,
+            )
+            global_attn_mask.fill_(float("-inf"))
+            # Fill the lower triangle with 0 (causal attention)
+            global_attn_mask = global_attn_mask.triu(diagonal=1)
+
+            # Enable bidirectional attention between image tokens
+            img_mask = torch.zeros_like(global_attn_mask)
+            img_mask[:, :, :, img_pos] += 1
+            img_mask[:, :, img_pos, :] += 1
+            global_attn_mask = torch.where(img_mask == 2, 0, global_attn_mask)
+            global_attn_masks.append(global_attn_mask)
+
+            # GGUF compatibility: config might be Gemma3TextConfig directly
+            text_config = getattr(self.config, "text_config", self.config)
+            sliding_window = text_config.sliding_window
+            if sliding_window is not None:
+                # Create a local causal mask with sliding window (1024)
+                local_attn_mask = torch.ones_like(global_attn_mask)
+                local_attn_mask = torch.tril(local_attn_mask, diagonal=-sliding_window)
+                local_attn_mask = torch.where(
+                    local_attn_mask == 0, global_attn_mask, float("-inf")
+                )
+                local_attn_masks.append(local_attn_mask)
+
+        return {
+            "has_images": True,
+            "seq_lens": seq_lens,
+            "global_attn_masks": global_attn_masks,
+            "local_attn_masks": local_attn_masks,
+        }
+
     def prepare_attn_masks(
         self,
         input_ids: torch.Tensor,
diff --git a/vllm/model_executor/models/siglip.py b/vllm/model_executor/models/siglip.py
index b175dd60c..42d906d08 100644
--- a/vllm/model_executor/models/siglip.py
+++ b/vllm/model_executor/models/siglip.py
@@ -827,6 +827,7 @@ class SiglipVisionModel(nn.Module):
     ) -> None:
         super().__init__()
 
+        self.quant_config = quant_config
         self.vision_model = SiglipVisionTransformer(
             config,
             quant_config,
@@ -911,12 +912,38 @@ class SiglipVisionModel(nn.Module):
                 break
             else:
                 param = params_dict[name]
+                param = maybe_swap_ffn_param(
+                    name, param, loaded_weight, params_dict, self.quant_config
+                )
                 weight_loader = getattr(param, "weight_loader", default_weight_loader)
                 weight_loader(param, loaded_weight)
             loaded_params.add(name)
         return loaded_params
 
 
+def maybe_swap_ffn_param(
+    name: str,
+    param: torch.Tensor,
+    loaded_weight: torch.Tensor,
+    params_dict: dict[str, torch.Tensor],
+    quant_config: QuantizationConfig,
+) -> torch.Tensor:
+    if not (quant_config and quant_config.get_name() == "gguf") or ".fc" not in name:
+        return param
+    # Some GGUF models have fc1 and fc2 weights swapped
+    tp_size = get_tensor_model_parallel_world_size()
+    output_dim = getattr(param, "output_dim", 0)
+    output_size = param.size(output_dim) * tp_size
+    weight_out_size = loaded_weight.size(output_dim)
+    if ".fc1." in name and output_size != weight_out_size:
+        new_name = name.replace(".fc1.", ".fc2.")
+        param = params_dict[new_name]
+    elif ".fc2." in name and output_size != weight_out_size:
+        new_name = name.replace(".fc2.", ".fc1.")
+        param = params_dict[new_name]
+    return param
+
+
 # Adapted from: https://github.com/huggingface/transformers/blob/v4.54.1/src/transformers/models/siglip/modeling_siglip.py#L200
 class SiglipTextEmbeddings(nn.Module):
     def __init__(self, config: SiglipTextConfig):
diff --git a/vllm/transformers_utils/config.py b/vllm/transformers_utils/config.py
index 49250e071..ac4a71648 100644
--- a/vllm/transformers_utils/config.py
+++ b/vllm/transformers_utils/config.py
@@ -477,6 +477,17 @@ def is_interleaved(config: PretrainedConfig) -> bool:
     return False
 
 
+def uses_custom_attention_masks(config: PretrainedConfig) -> bool:
+    """Detect if model uses custom attention mask generation for multimodal.
+
+    Some multimodal models require custom attention masks that enable
+    bidirectional attention between image tokens while maintaining causal
+    attention for text tokens. Currently applies to Gemma3 multimodal models.
+    """
+    architectures = getattr(config, "architectures", [])
+    return "Gemma3ForConditionalGeneration" in architectures
+
+
 def _maybe_update_auto_config_kwargs(kwargs: dict[str, Any], model_type: str):
     """
     Update kwargs for AutoConfig initialization based on model_type
diff --git a/vllm/transformers_utils/gguf_utils.py b/vllm/transformers_utils/gguf_utils.py
new file mode 100644
index 000000000..2bf59c91a
--- /dev/null
+++ b/vllm/transformers_utils/gguf_utils.py
@@ -0,0 +1,166 @@
+# SPDX-License-Identifier: Apache-2.0
+# SPDX-FileCopyrightText: Copyright contributors to the vLLM project
+"""GGUF utility functions."""
+
+from pathlib import Path
+
+import gguf
+from gguf.constants import Keys, VisionProjectorType
+from transformers import Gemma3Config, PretrainedConfig, SiglipVisionConfig
+
+from vllm.logger import init_logger
+
+logger = init_logger(__name__)
+
+
+def detect_gguf_multimodal(model: str) -> Path | None:
+    """Check if GGUF model has multimodal projector file.
+
+    Args:
+        model: Model path string
+
+    Returns:
+        Path to mmproj file if found, None otherwise
+    """
+    if not model.endswith(".gguf"):
+        return None
+
+    try:
+        model_path = Path(model)
+        if not model_path.is_file():
+            return None
+
+        model_dir = model_path.parent
+        mmproj_patterns = ["mmproj.gguf", "mmproj-*.gguf", "*mmproj*.gguf"]
+        for pattern in mmproj_patterns:
+            mmproj_files = list(model_dir.glob(pattern))
+            if mmproj_files:
+                return mmproj_files[0]
+        return None
+    except Exception:
+        return None
+
+
+def extract_vision_config_from_gguf(mmproj_path: str) -> "SiglipVisionConfig | None":
+    """Extract vision config parameters from mmproj.gguf metadata.
+
+    Reads vision encoder configuration from GGUF metadata fields using
+    standardized GGUF constants. Automatically detects the projector type
+    (e.g., gemma3, llama4) and applies model-specific parameters accordingly.
+
+    The function extracts standard CLIP vision parameters from GGUF metadata
+    and applies projector-type-specific customizations. For unknown projector
+    types, it uses safe defaults from SiglipVisionConfig.
+
+    Args:
+        mmproj_path: Path to mmproj.gguf file (str or Path)
+
+    Returns:
+        SiglipVisionConfig if extraction succeeds, None if any required
+        field is missing from the GGUF metadata
+
+    Raises:
+        Exception: Exceptions from GGUF reading (file not found, corrupted
+            file, etc.) propagate directly from gguf.GGUFReader
+    """
+    reader = gguf.GGUFReader(str(mmproj_path))
+
+    # Detect projector type to apply model-specific parameters
+    projector_type = None
+    projector_type_field = reader.get_field(Keys.Clip.PROJECTOR_TYPE)
+    if projector_type_field:
+        try:
+            projector_type = bytes(projector_type_field.parts[-1]).decode("utf-8")
+        except (AttributeError, UnicodeDecodeError) as e:
+            logger.warning("Failed to decode projector type from GGUF: %s", e)
+
+    # Map GGUF field constants to SiglipVisionConfig parameters.
+    # Uses official GGUF constants from gguf-py for standardization.
+    # Format: {gguf_constant: (param_name, dtype)}
+    VISION_CONFIG_FIELDS = {
+        Keys.ClipVision.EMBEDDING_LENGTH: ("hidden_size", int),
+        Keys.ClipVision.FEED_FORWARD_LENGTH: ("intermediate_size", int),
+        Keys.ClipVision.BLOCK_COUNT: ("num_hidden_layers", int),
+        Keys.ClipVision.Attention.HEAD_COUNT: ("num_attention_heads", int),
+        Keys.ClipVision.IMAGE_SIZE: ("image_size", int),
+        Keys.ClipVision.PATCH_SIZE: ("patch_size", int),
+        Keys.ClipVision.Attention.LAYERNORM_EPS: ("layer_norm_eps", float),
+    }
+
+    # Extract and validate all required fields
+    config_params = {}
+    for gguf_key, (param_name, dtype) in VISION_CONFIG_FIELDS.items():
+        field = reader.get_field(gguf_key)
+        if field is None:
+            logger.warning(
+                "Missing required vision config field '%s' in mmproj.gguf",
+                gguf_key,
+            )
+            return None
+        # Extract scalar value from GGUF field and convert to target type
+        config_params[param_name] = dtype(field.parts[-1])
+
+    # Apply model-specific parameters based on projector type
+    if projector_type == VisionProjectorType.GEMMA3:
+        # Gemma3 doesn't use the vision pooling head (multihead attention)
+        # This is a vLLM-specific parameter used in SiglipVisionTransformer
+        config_params["vision_use_head"] = False
+        logger.info("Detected Gemma3 projector, disabling vision pooling head")
+    # Add other projector-type-specific customizations here as needed
+    # elif projector_type == VisionProjectorType.LLAMA4:
+    #     config_params["vision_use_head"] = ...
+
+    # Create config with extracted parameters
+    # Note: num_channels and attention_dropout use SiglipVisionConfig defaults
+    # (3 and 0.0 respectively) which are correct for all models
+    config = SiglipVisionConfig(**config_params)
+
+    if projector_type:
+        logger.info(
+            "Extracted vision config from mmproj.gguf (projector_type: %s)",
+            projector_type,
+        )
+    else:
+        logger.info("Extracted vision config from mmproj.gguf metadata")
+
+    return config
+
+
+def maybe_patch_hf_config_from_gguf(
+    model: str,
+    hf_config: PretrainedConfig,
+) -> PretrainedConfig:
+    """Patch HF config for GGUF models.
+
+    Applies GGUF-specific patches to HuggingFace config:
+    1. For multimodal models: patches architecture and vision config
+    2. For all GGUF models: overrides vocab_size from embedding tensor
+
+    This ensures compatibility with GGUF models that have extended
+    vocabularies (e.g., Unsloth) where the GGUF file contains more
+    tokens than the HuggingFace tokenizer config specifies.
+
+    Args:
+        model: Model path string
+        hf_config: HuggingFace config to patch in-place
+
+    Returns:
+        Updated HuggingFace config
+    """
+    # Patch multimodal config if mmproj.gguf exists
+    mmproj_path = detect_gguf_multimodal(model)
+    if mmproj_path is not None:
+        vision_config = extract_vision_config_from_gguf(str(mmproj_path))
+
+        # Create HF config for Gemma3 multimodal
+        text_config = hf_config.get_text_config()
+        is_gemma3 = hf_config.model_type in ("gemma3", "gemma3_text")
+        if vision_config is not None and is_gemma3:
+            new_hf_config = Gemma3Config.from_text_vision_configs(
+                text_config=text_config,
+                vision_config=vision_config,
+                architectures=["Gemma3ForConditionalGeneration"],
+            )
+            hf_config = new_hf_config
+
+    return hf_config
diff --git a/vllm/transformers_utils/processor.py b/vllm/transformers_utils/processor.py
index b3469c1b1..8deacb5b0 100644
--- a/vllm/transformers_utils/processor.py
+++ b/vllm/transformers_utils/processor.py
@@ -18,7 +18,7 @@ from transformers.processing_utils import ProcessorMixin
 from transformers.video_processing_utils import BaseVideoProcessor
 from typing_extensions import TypeVar
 
-from vllm.transformers_utils.utils import convert_model_repo_to_path
+from vllm.transformers_utils.utils import check_gguf_file, convert_model_repo_to_path
 from vllm.utils.func_utils import get_allowed_kwarg_only_overrides
 
 if TYPE_CHECKING:
@@ -236,9 +236,20 @@ def cached_processor_from_config(
     processor_cls: type[_P] | tuple[type[_P], ...] = ProcessorMixin,
     **kwargs: Any,
 ) -> _P:
+    if check_gguf_file(model_config.model):
+        assert not check_gguf_file(model_config.tokenizer), (
+            "For multimodal GGUF models, the original tokenizer "
+            "should be used to correctly load processor."
+        )
+        model = model_config.tokenizer
+        revision = model_config.tokenizer_revision
+    else:
+        model = model_config.model
+        revision = model_config.revision
+
     return cached_get_processor_without_dynamic_kwargs(
-        model_config.model,
-        revision=model_config.revision,
+        model,
+        revision=revision,
         trust_remote_code=model_config.trust_remote_code,
         processor_cls=processor_cls,  # type: ignore[arg-type]
         **_merge_mm_kwargs(model_config, processor_cls, **kwargs),
@@ -339,9 +350,19 @@ def cached_image_processor_from_config(
     model_config: "ModelConfig",
     **kwargs: Any,
 ):
+    if check_gguf_file(model_config.model):
+        assert not check_gguf_file(model_config.tokenizer), (
+            "For multimodal GGUF models, the original tokenizer "
+            "should be used to correctly load image processor."
+        )
+        model = model_config.tokenizer
+        revision = model_config.tokenizer_revision
+    else:
+        model = model_config.model
+        revision = model_config.revision
     return cached_get_image_processor(
-        model_config.model,
-        revision=model_config.revision,
+        model,
+        revision=revision,
         trust_remote_code=model_config.trust_remote_code,
         **_merge_mm_kwargs(model_config, AutoImageProcessor, **kwargs),
     )
diff --git a/vllm/transformers_utils/utils.py b/vllm/transformers_utils/utils.py
index 1ae42ba62..901a64d9d 100644
--- a/vllm/transformers_utils/utils.py
+++ b/vllm/transformers_utils/utils.py
@@ -27,6 +27,7 @@ def is_cloud_storage(model_or_path: str) -> bool:
     return is_s3(model_or_path) or is_gcs(model_or_path)
 
 
+@cache
 def check_gguf_file(model: str | PathLike) -> bool:
     """Check if the file is a GGUF model."""
     model = Path(model)
diff --git a/vllm/v1/worker/gpu_model_runner.py b/vllm/v1/worker/gpu_model_runner.py
index 0102ca473..67f575f92 100644
--- a/vllm/v1/worker/gpu_model_runner.py
+++ b/vllm/v1/worker/gpu_model_runner.py
@@ -324,6 +324,7 @@ class GPUModelRunner(
         # Multi-modal data support
         self.mm_registry = MULTIMODAL_REGISTRY
         self.uses_mrope = model_config.uses_mrope
+        self.uses_custom_attention_masks = model_config.uses_custom_attention_masks
         self.supports_mm_inputs = self.mm_registry.supports_multimodal_inputs(
             model_config
         )
@@ -2346,6 +2347,24 @@ class GPUModelRunner(
                 **self._init_model_kwargs(num_scheduled_tokens),
                 **self._extract_mm_kwargs(scheduler_output),
             }
+
+            # Generate custom attention masks for models that require them.
+            # V1 pre-generates embeddings, so forward() skips prepare_attn_masks().
+            # Check mm_features (mm_embeds is empty during decode).
+            has_mm_features = any(
+                req_state.mm_features for req_state in self.requests.values()
+            )
+            if (
+                self.uses_custom_attention_masks
+                and has_mm_features
+                and hasattr(self.model, "generate_attention_masks")
+            ):
+                mask_kwargs = self.model.generate_attention_masks(
+                    self.input_ids.gpu[:num_scheduled_tokens],
+                    self.positions.gpu[:num_scheduled_tokens],
+                    mask_dtype=self.model.dtype,
+                )
+                model_kwargs.update(mask_kwargs)
         elif self.enable_prompt_embeds and is_first_rank:
             # Get the input embeddings for the tokens that are not input embeds,
             # then put them into the appropriate positions.