diff --git a/python/sglang/srt/entrypoints/openai/protocol.py b/python/sglang/srt/entrypoints/openai/protocol.py
index 6da7c8889..ed52f535c 100644
--- a/python/sglang/srt/entrypoints/openai/protocol.py
+++ b/python/sglang/srt/entrypoints/openai/protocol.py
@@ -460,6 +460,38 @@ class ChatCompletionRequest(BaseModel):
                 values["tool_choice"] = "auto"
         return values
 
+    @model_validator(mode="before")
+    @classmethod
+    def set_json_schema(cls, values):
+        response_format = values.get("response_format")
+        if not response_format:
+            return values
+
+        if response_format.get("type") != "json_schema":
+            return values
+
+        schema = response_format.pop("schema", None)
+        json_schema = response_format.get("json_schema")
+
+        if json_schema:
+            return values
+
+        if schema:
+            name_ = schema.get("title", "Schema")
+            strict_ = False
+            if "properties" in schema and "strict" in schema["properties"]:
+                item = schema["properties"].pop("strict", None)
+                if item and item.get("default", False):
+                    strict_ = True
+
+            response_format["json_schema"] = {
+                "name": name_,
+                "schema": schema,
+                "strict": strict_,
+            }
+
+        return values
+
     # Extra parameters for SRT backend only and will be ignored by OpenAI models.
     top_k: int = -1
     min_p: float = 0.0
diff --git a/test/srt/openai_server/basic/test_protocol.py b/test/srt/openai_server/basic/test_protocol.py
index 65b4e4c50..9066e5339 100644
--- a/test/srt/openai_server/basic/test_protocol.py
+++ b/test/srt/openai_server/basic/test_protocol.py
@@ -18,7 +18,7 @@ import time
 import unittest
 from typing import Dict, List, Optional
 
-from pydantic import ValidationError
+from pydantic import BaseModel, Field, ValidationError
 
 from sglang.srt.entrypoints.openai.protocol import (
     BatchRequest,
@@ -192,6 +192,81 @@ class TestChatCompletionRequest(unittest.TestCase):
         self.assertFalse(request.stream_reasoning)
         self.assertEqual(request.chat_template_kwargs, {"custom_param": "value"})
 
+    def test_chat_completion_json_format(self):
+        """Test chat completion json format"""
+        transcript = "Good morning! It's 7:00 AM, and I'm just waking up. Today is going to be a busy day, "
+        "so let's get started. First, I need to make a quick breakfast. I think I'll have some "
+        "scrambled eggs and toast with a cup of coffee. While I'm cooking, I'll also check my "
+        "emails to see if there's anything urgent."
+
+        messages = [
+            {
+                "role": "system",
+                "content": "The following is a voice message transcript. Only answer in JSON.",
+            },
+            {
+                "role": "user",
+                "content": transcript,
+            },
+        ]
+
+        class VoiceNote(BaseModel):
+            title: str = Field(description="A title for the voice note")
+            summary: str = Field(
+                description="A short one sentence summary of the voice note."
+            )
+            strict: Optional[bool] = True
+            actionItems: List[str] = Field(
+                description="A list of action items from the voice note"
+            )
+
+        request = ChatCompletionRequest(
+            model="test-model",
+            messages=messages,
+            top_k=40,
+            min_p=0.05,
+            separate_reasoning=False,
+            stream_reasoning=False,
+            chat_template_kwargs={"custom_param": "value"},
+            response_format={
+                "type": "json_schema",
+                "schema": VoiceNote.model_json_schema(),
+            },
+        )
+        res_format = request.response_format
+        json_format = res_format.json_schema
+        name = json_format.name
+        schema = json_format.schema_
+        strict = json_format.strict
+        self.assertEqual(name, "VoiceNote")
+        self.assertEqual(strict, True)
+        self.assertNotIn("strict", schema["properties"])
+
+        request = ChatCompletionRequest(
+            model="test-model",
+            messages=messages,
+            top_k=40,
+            min_p=0.05,
+            separate_reasoning=False,
+            stream_reasoning=False,
+            chat_template_kwargs={"custom_param": "value"},
+            response_format={
+                "type": "json_schema",
+                "json_schema": {
+                    "name": "VoiceNote",
+                    "schema": VoiceNote.model_json_schema(),
+                    "strict": True,
+                },
+            },
+        )
+        res_format = request.response_format
+        json_format = res_format.json_schema
+        name = json_format.name
+        schema = json_format.schema_
+        strict = json_format.strict
+        self.assertEqual(name, "VoiceNote")
+        self.assertEqual(strict, True)
+
 
 class TestModelSerialization(unittest.TestCase):
     """Test model serialization with hidden states"""