diff --git a/docs/models/supported_models.md b/docs/models/supported_models.md
index 989bd5fff..355ac5709 100644
--- a/docs/models/supported_models.md
+++ b/docs/models/supported_models.md
@@ -593,7 +593,7 @@ Specified using `--task generate`.
 | `GraniteSpeechForConditionalGeneration` | Granite Speech | T + A | `ibm-granite/granite-speech-3.3-8b` | ✅︎ | ✅︎ | ✅︎ |
 | `H2OVLChatModel` | H2OVL | T + I<sup>E+</sup> | `h2oai/h2ovl-mississippi-800m`, `h2oai/h2ovl-mississippi-2b`, etc. | | ✅︎ | ✅︎ |
 | `Idefics3ForConditionalGeneration` | Idefics3 | T + I | `HuggingFaceM4/Idefics3-8B-Llama3`, etc. | ✅︎ | | ✅︎ |
-| `InternS1ForConditionalGeneration` | Intern-S1 | T + I<sup>E+</sup> | `internlm/Intern-S1`, etc. | | ✅︎ | ✅︎ |
+| `InternS1ForConditionalGeneration` | Intern-S1 | T + I<sup>E+</sup> + V<sup>E+</sup> | `internlm/Intern-S1`, etc. | | ✅︎ | ✅︎ |
 | `InternVLChatModel` | InternVL 3.0, InternVideo 2.5, InternVL 2.5, Mono-InternVL, InternVL 2.0 | T + I<sup>E+</sup> + (V<sup>E+</sup>) | `OpenGVLab/InternVL3-9B`, `OpenGVLab/InternVideo2_5_Chat_8B`, `OpenGVLab/InternVL2_5-4B`, `OpenGVLab/Mono-InternVL-2B`, `OpenGVLab/InternVL2-4B`, etc. | ✅︎ | ✅︎ | ✅︎ |
 | `KeyeForConditionalGeneration` | Keye-VL-8B-Preview | T + I<sup>E+</sup> + V<sup>E+</sup> | `Kwai-Keye/Keye-VL-8B-Preview` | | | ✅︎ |
 | `KimiVLForConditionalGeneration` | Kimi-VL-A3B-Instruct, Kimi-VL-A3B-Thinking | T + I<sup>+</sup> | `moonshotai/Kimi-VL-A3B-Instruct`, `moonshotai/Kimi-VL-A3B-Thinking` | | | ✅︎ |
diff --git a/examples/offline_inference/vision_language.py b/examples/offline_inference/vision_language.py
index 8af591102..6f23a29e7 100644
--- a/examples/offline_inference/vision_language.py
+++ b/examples/offline_inference/vision_language.py
@@ -470,8 +470,6 @@ def run_tarsier(questions: list[str], modality: str) -> ModelRequestData:
 
 # Intern-S1
 def run_interns1(questions: list[str], modality: str) -> ModelRequestData:
-    assert modality == "image"
-
     model_name = "internlm/Intern-S1"
 
     engine_args = EngineArgs(
@@ -483,7 +481,11 @@ def run_interns1(questions: list[str], modality: str) -> ModelRequestData:
         enforce_eager=True,
     )
 
-    placeholder = "<IMG_CONTEXT>"
+    if modality == "image":
+        placeholder = "<IMG_CONTEXT>"
+    elif modality == "video":
+        placeholder = "<video>"
+
     tokenizer = AutoTokenizer.from_pretrained(model_name, trust_remote_code=True)
     messages = [
         [{"role": "user", "content": f"{placeholder}\n{question}"}]
diff --git a/tests/models/multimodal/processing/test_common.py b/tests/models/multimodal/processing/test_common.py
index 03bdafdbb..640547719 100644
--- a/tests/models/multimodal/processing/test_common.py
+++ b/tests/models/multimodal/processing/test_common.py
@@ -278,6 +278,7 @@ def _test_processing_correctness_one(
     "THUDM/GLM-4.1V-9B-Thinking",
     "ibm-granite/granite-speech-3.3-2b",
     "h2oai/h2ovl-mississippi-800m",
+    "internlm/Intern-S1",
     "OpenGVLab/InternVL2-1B",
     "OpenGVLab/InternVL3-1B",
     "HuggingFaceM4/Idefics3-8B-Llama3",
diff --git a/vllm/model_executor/models/interns1.py b/vllm/model_executor/models/interns1.py
index 36204e4c5..ab21cbe91 100644
--- a/vllm/model_executor/models/interns1.py
+++ b/vllm/model_executor/models/interns1.py
@@ -9,9 +9,10 @@
 from collections.abc import Iterable, Mapping, Sequence
 from typing import Literal, Optional, TypedDict, Union
 
+import regex as re
 import torch
 import torch.nn as nn
-from transformers import InternVLProcessor, PretrainedConfig
+from transformers import BatchFeature, InternVLProcessor, PretrainedConfig
 from transformers.activations import ACT2FN
 from transformers.models.got_ocr2.image_processing_got_ocr2_fast import (
     GotOcr2ImageProcessorFast)
@@ -139,13 +140,13 @@ def get_interns1_target_ratios(
 
 
 class InternS1ProcessingInfo(BaseProcessingInfo):
-    """Basic image-only ProcessingInfo for InternS1-style models."""
+    """ProcessingInfo for InternS1-style models."""
 
     def get_hf_processor(self, **kwargs: object) -> InternVLProcessor:
         return self.ctx.get_hf_processor(InternVLProcessor, **kwargs)
 
     def get_supported_mm_limits(self) -> Mapping[str, Optional[int]]:
-        return {"image": None}
+        return {"image": None, "video": None}
 
     def get_num_image_tokens(
         self,
@@ -218,16 +219,35 @@ class InternS1ProcessingInfo(BaseProcessingInfo):
             processor=processor.image_processor,
         )
 
+    def get_num_frames_with_most_features(
+        self,
+        seq_len: int,
+        mm_counts: Mapping[str, int],
+    ) -> int:
+        max_images = mm_counts.get("image", 0)
+        max_videos = mm_counts.get("video", 0)
+
+        processor = self.get_hf_processor()
+
+        max_image_tokens = self.get_max_image_tokens() * max_images
+        max_total_frames = (seq_len -
+                            max_image_tokens) // processor.image_seq_length
+        max_frames_per_video = max_total_frames // max(max_videos, 1)
+
+        return max(max_frames_per_video, 1)
+
 
 class InternS1DummyInputsBuilder(BaseDummyInputsBuilder[InternS1ProcessingInfo]
                                  ):
-    """Basic image-only DummyInputsBuilder for InternS1-style models."""
+    """DummyInputsBuilder for InternS1-style models."""
 
     def get_dummy_text(self, mm_counts: Mapping[str, int]) -> str:
         num_images = mm_counts.get("image", 0)
+        num_videos = mm_counts.get("video", 0)
         image_token = self.info.get_hf_processor().image_token
+        video_token = self.info.get_hf_processor().video_token
 
-        return image_token * num_images
+        return image_token * num_images + video_token * num_videos
 
     def get_dummy_mm_data(
         self,
@@ -236,13 +256,24 @@ class InternS1DummyInputsBuilder(BaseDummyInputsBuilder[InternS1ProcessingInfo]
     ) -> MultiModalDataDict:
         target_width, target_height = \
             self.info.get_image_size_with_most_features()
+        target_num_frames = \
+                self.info.get_num_frames_with_most_features(seq_len, mm_counts)
         num_images = mm_counts.get("image", 0)
+        num_videos = mm_counts.get("video", 0)
+
+        config = self.info.get_hf_config()
+        image_size_h, image_size_w = config.vision_config.image_size
 
         return {
             "image":
             self._get_dummy_images(width=target_width,
                                    height=target_height,
-                                   num_images=num_images)
+                                   num_images=num_images),
+            "video":
+            self._get_dummy_videos(width=image_size_w,
+                                   height=image_size_h,
+                                   num_frames=target_num_frames,
+                                   num_videos=num_videos),
         }
 
 
@@ -257,33 +288,89 @@ class InternS1MultiModalProcessor(
         mm_kwargs: Mapping[str, object],
         tok_kwargs: Mapping[str, object],
     ) -> Mapping[str, NestedTensors]:
-        processed_outputs = super()._call_hf_processor(
-            prompt=prompt,
-            mm_data=mm_data,
-            mm_kwargs=mm_kwargs,
-            tok_kwargs=tok_kwargs,
-        )
+        mm_data = dict(mm_data)
+        videos = mm_data.pop("videos", [])
+        images = mm_data.pop("images", [])
+        assert isinstance(videos, list)
+        assert isinstance(images, list)
 
         hf_processor = self.info.get_hf_processor(**mm_kwargs)
-        image_token_id = hf_processor.image_token_id
+        tokenizer = hf_processor.tokenizer
+        video_token_id = tokenizer.encode(hf_processor.video_token,
+                                          add_special_tokens=False)
+        assert len(video_token_id) == 1
+        video_token_id = video_token_id[0]
 
-        # Since there may be extra tokens in the feature placeholders,
-        # we need to pass the image token ID to the model to select the
-        # tokens to merge from the vision encoder outputs
-        processed_outputs["image_token_id"] = torch.tensor(image_token_id)
-        images = mm_data.get('images', None)
-        image_processor = self.info.get_hf_processor().image_processor
-        if images is not None:
-            image_inputs = image_processor(images=images)
-            image_num_patches = image_inputs.pop("num_patches")
-            if not isinstance(image_num_patches, list):
-                raise ValueError(
-                    f'num_patches is supposed to be list, but got '
-                    f'{type(image_num_patches)}')
-            image_num_patches = torch.tensor(image_num_patches)
-            processed_outputs['image_num_patches'] = image_num_patches
+        prompt = re.sub(hf_processor.image_token, "<image_placeholder>",
+                        prompt)
+        prompt = re.sub(hf_processor.video_token, "<video_placeholder>",
+                        prompt)
 
-        return processed_outputs
+        image_outputs = {}
+        if images:
+            image_pixel_values = []
+            for image in images:
+                processed_outputs = super()._call_hf_processor(
+                    prompt=hf_processor.image_token,
+                    mm_data={"images": image},
+                    mm_kwargs=mm_kwargs,
+                    tok_kwargs=tok_kwargs,
+                )
+                image_pixel_values.append(
+                    processed_outputs.pop("pixel_values"))
+
+                input_ids = processed_outputs.pop("input_ids")
+                image_placeholder = tokenizer.batch_decode(input_ids)[0]
+                prompt = prompt.replace("<image_placeholder>",
+                                        image_placeholder, 1)
+
+            num_patches = [len(item) for item in image_pixel_values]
+            image_outputs: dict[str, NestedTensors] = {
+                "pixel_values": torch.concat(image_pixel_values),
+                "image_num_patches": torch.tensor(num_patches),
+                "image_token_id": torch.tensor(hf_processor.image_token_id),
+            }
+
+        video_outputs = {}
+        if videos:
+            video_pixel_values = []
+            for video in videos:
+                processed_outputs = super()._call_hf_processor(
+                    prompt=hf_processor.video_token,
+                    mm_data={"videos": video},
+                    mm_kwargs=mm_kwargs,
+                    tok_kwargs=tok_kwargs,
+                )
+                video_pixel_values.append(
+                    processed_outputs.pop("pixel_values"))
+
+                input_ids = processed_outputs.pop("input_ids")
+                input_ids[input_ids ==
+                          hf_processor.image_token_id] = video_token_id
+
+                video_placeholder = tokenizer.batch_decode(input_ids)[0]
+                prompt = prompt.replace("<video_placeholder>",
+                                        video_placeholder, 1)
+
+            num_frames = [len(item) for item in video_pixel_values]
+            video_outputs: dict[str, NestedTensors] = {
+                "pixel_values_videos": torch.concat(video_pixel_values),
+                "video_num_patches": torch.tensor(num_frames),
+                "video_token_id": torch.tensor(video_token_id),
+            }
+
+        prompt = re.sub("<image_placeholder>", hf_processor.image_token,
+                        prompt)
+        prompt = re.sub("<video_placeholder>", hf_processor.video_token,
+                        prompt)
+        text_outputs = tokenizer(prompt, **tok_kwargs, return_tensors="pt")
+
+        combined_outputs = dict(
+            **text_outputs,
+            **image_outputs,
+            **video_outputs,
+        )
+        return BatchFeature(combined_outputs)
 
     def _get_mm_fields_config(
         self,
@@ -292,7 +379,9 @@ class InternS1MultiModalProcessor(
     ) -> Mapping[str, MultiModalFieldConfig]:
 
         image_num_patches = hf_inputs.get("image_num_patches", torch.empty(0))
+        video_num_patches = hf_inputs.get("video_num_patches", torch.empty(0))
         num_images = len(image_num_patches)
+        num_videos = len(video_num_patches)
 
         return dict(
             pixel_values=MultiModalFieldConfig.flat_from_sizes(
@@ -300,6 +389,10 @@ class InternS1MultiModalProcessor(
             image_num_patches=MultiModalFieldConfig.batched("image"),
             image_embeds=MultiModalFieldConfig.batched("image"),
             image_token_id=MultiModalFieldConfig.shared("image", num_images),
+            pixel_values_videos=MultiModalFieldConfig.flat_from_sizes(
+                "video", video_num_patches),
+            video_num_patches=MultiModalFieldConfig.batched("video"),
+            video_token_id=MultiModalFieldConfig.shared("video", num_videos),
         )
 
     def _get_prompt_updates(
@@ -312,32 +405,61 @@ class InternS1MultiModalProcessor(
         img_context_token = hf_processor.image_token
         start_image_token = hf_processor.start_image_token
         end_image_token = hf_processor.end_image_token
+        video_token = hf_processor.video_token
 
-        def get_replacement(item_idx: int):
+        if "video_num_patches" in out_mm_kwargs:
+            video_num_patches = out_mm_kwargs["video_num_patches"]
+            assert isinstance(video_num_patches, torch.Tensor)
+            video_num_patches = video_num_patches.tolist()
+        else:
+            video_num_patches = []
+
+        if "image_num_patches" in out_mm_kwargs:
+            image_num_patches = out_mm_kwargs["image_num_patches"]
+            assert isinstance(image_num_patches, torch.Tensor)
+            image_num_patches = image_num_patches.tolist()
+        else:
+            image_num_patches = []
+
+        def get_replacement_interns1_image(item_idx: int):
             images = mm_items.get_items(
                 "image", (ImageEmbeddingItems, ImageProcessorItems))
 
             if isinstance(images, ImageEmbeddingItems):
                 feature_size = images.get_feature_size(item_idx)
             else:
-                image_size = images.get_image_size(item_idx)
-                feature_size = self.info.get_num_image_tokens(
-                    image_width=image_size.width,
-                    image_height=image_size.height,
-                    processor=hf_processor.image_processor,
-                )
+                num_patches = image_num_patches[item_idx]
+                feature_size = num_patches * hf_processor.image_seq_length
 
             repl_features = img_context_token * feature_size
             repl_full = start_image_token + repl_features + end_image_token
             return PromptUpdateDetails.select_text(repl_full,
                                                    img_context_token)
 
+        def get_replacement_interns1_video(item_idx: int):
+            num_patches = video_num_patches[item_idx]
+            repl_features = video_token * hf_processor.image_seq_length
+            repl_features_with_sep = (start_image_token + repl_features +
+                                      end_image_token)
+            # num_patches is equal to num_frames
+            repl_full = '\n'.join([
+                f'Frame{i+1}: {repl_features_with_sep}'
+                for i in range(num_patches)
+            ])
+
+            return PromptUpdateDetails.select_text(repl_full, video_token)
+
         return [
             PromptReplacement(
                 modality="image",
                 target=img_context_token,
-                replacement=get_replacement,
-            )
+                replacement=get_replacement_interns1_image,
+            ),
+            PromptReplacement(
+                modality="video",
+                target=video_token,
+                replacement=get_replacement_interns1_video,
+            ),
         ]
 
 
@@ -514,7 +636,7 @@ class InternS1ForConditionalGeneration(nn.Module, SupportsMultiModal,
 
     def _parse_and_validate_video_input(
             self, **kwargs: object) -> Optional[InternS1VideoPixelInputs]:
-        pixel_values_flat_video = kwargs.pop("pixel_values_flat_video", None)
+        pixel_values_flat_video = kwargs.pop("pixel_values_videos", None)
         video_num_patches = kwargs.pop("video_num_patches", None)
         video_embeds = kwargs.pop("video_embeds", None)
 
@@ -595,8 +717,8 @@ class InternS1ForConditionalGeneration(nn.Module, SupportsMultiModal,
                              "image_embeds") and "images" not in modalities:
                 modalities["images"] = self._parse_and_validate_image_input(
                     **kwargs)
-            if input_key in ("pixel_values_flat_video",
-                             ) and "videos" not in modalities:
+            if input_key in (
+                    "pixel_values_videos", ) and "videos" not in modalities:
                 modalities["videos"] = self._parse_and_validate_video_input(
                     **kwargs)
 
@@ -614,7 +736,6 @@ class InternS1ForConditionalGeneration(nn.Module, SupportsMultiModal,
         modalities = self._parse_and_validate_multimodal_inputs(**kwargs)
         if not modalities:
             return []
-            return None
 
         # The result multimodal_embeddings is tuple of tensors, with each
         # tensor correspoending to a multimodal data item (image or video).
diff --git a/vllm/model_executor/models/internvl.py b/vllm/model_executor/models/internvl.py
index f8b9ea2c5..3637f0377 100644
--- a/vllm/model_executor/models/internvl.py
+++ b/vllm/model_executor/models/internvl.py
@@ -1322,7 +1322,6 @@ class InternVLChatModel(nn.Module, SupportsMultiModal, SupportsPP,
         modalities = self._parse_and_validate_multimodal_inputs(**kwargs)
         if not modalities:
             return []
-            return None
 
         # The result multimodal_embeddings is tuple of tensors, with each
         # tensor correspoending to a multimodal data item (image or video).