diff --git a/litellm/llms/anthropic/experimental_pass_through/adapters/handler.py b/litellm/llms/anthropic/experimental_pass_through/adapters/handler.py
index 795f9a4cd09..8fa7bb7e65e 100644
--- a/litellm/llms/anthropic/experimental_pass_through/adapters/handler.py
+++ b/litellm/llms/anthropic/experimental_pass_through/adapters/handler.py
@@ -45,6 +45,7 @@ class LiteLLMMessagesToCompletionTransformationHandler:
         tools: Optional[List[Dict]] = None,
         top_k: Optional[int] = None,
         top_p: Optional[float] = None,
+        output_format: Optional[Dict] = None,
         extra_kwargs: Optional[Dict[str, Any]] = None,
     ) -> Dict[str, Any]:
         """Prepare kwargs for litellm.completion/acompletion"""
@@ -76,6 +77,8 @@ class LiteLLMMessagesToCompletionTransformationHandler:
             request_data["top_k"] = top_k
         if top_p is not None:
             request_data["top_p"] = top_p
+        if output_format:
+            request_data["output_format"] = output_format
 
         openai_request = ANTHROPIC_ADAPTER.translate_completion_input_params(
             request_data
@@ -130,6 +133,7 @@ class LiteLLMMessagesToCompletionTransformationHandler:
         tools: Optional[List[Dict]] = None,
         top_k: Optional[int] = None,
         top_p: Optional[float] = None,
+        output_format: Optional[Dict] = None,
         **kwargs,
     ) -> Union[AnthropicMessagesResponse, AsyncIterator]:
         """Handle non-Anthropic models asynchronously using the adapter"""
@@ -148,6 +152,7 @@ class LiteLLMMessagesToCompletionTransformationHandler:
                 tools=tools,
                 top_k=top_k,
                 top_p=top_p,
+                output_format=output_format,
                 extra_kwargs=kwargs,
             )
         )
@@ -189,6 +194,7 @@ class LiteLLMMessagesToCompletionTransformationHandler:
         tools: Optional[List[Dict]] = None,
         top_k: Optional[int] = None,
         top_p: Optional[float] = None,
+        output_format: Optional[Dict] = None,
         _is_async: bool = False,
         **kwargs,
     ) -> Union[
@@ -212,6 +218,7 @@ class LiteLLMMessagesToCompletionTransformationHandler:
                 tools=tools,
                 top_k=top_k,
                 top_p=top_p,
+                output_format=output_format,
                 **kwargs,
             )
 
@@ -230,6 +237,7 @@ class LiteLLMMessagesToCompletionTransformationHandler:
                 tools=tools,
                 top_k=top_k,
                 top_p=top_p,
+                output_format=output_format,
                 extra_kwargs=kwargs,
             )
         )
diff --git a/litellm/llms/anthropic/experimental_pass_through/adapters/transformation.py b/litellm/llms/anthropic/experimental_pass_through/adapters/transformation.py
index 877e47a9aea..1706f045f14 100644
--- a/litellm/llms/anthropic/experimental_pass_through/adapters/transformation.py
+++ b/litellm/llms/anthropic/experimental_pass_through/adapters/transformation.py
@@ -172,7 +172,7 @@ class LiteLLMAnthropicMessagesAdapter:
         """
         Which anthropic params, we need to translate to the openai format.
         """
-        return ["messages", "metadata", "system", "tool_choice", "tools", "thinking"]
+        return ["messages", "metadata", "system", "tool_choice", "tools", "thinking", "output_format"]
 
     def translate_anthropic_messages_to_openai(  # noqa: PLR0915
         self,
@@ -554,6 +554,42 @@ class LiteLLMAnthropicMessagesAdapter:
 
         return new_tools
 
+    def translate_anthropic_output_format_to_openai(
+        self, output_format: Any
+    ) -> Optional[Dict[str, Any]]:
+        """
+        Translate Anthropic's output_format to OpenAI's response_format.
+
+        Anthropic output_format: {"type": "json_schema", "schema": {...}}
+        OpenAI response_format: {"type": "json_schema", "json_schema": {"name": "...", "schema": {...}}}
+
+        Args:
+            output_format: Anthropic output_format dict with 'type' and 'schema'
+
+        Returns:
+            OpenAI-compatible response_format dict, or None if invalid
+        """
+        if not isinstance(output_format, dict):
+            return None
+
+        output_type = output_format.get("type")
+        if output_type != "json_schema":
+            return None
+
+        schema = output_format.get("schema")
+        if not schema:
+            return None
+
+        # Convert to OpenAI response_format structure
+        return {
+            "type": "json_schema",
+            "json_schema": {
+                "name": "structured_output",
+                "schema": schema,
+                "strict": True,
+            },
+        }
+
     def translate_anthropic_to_openai(
         self, anthropic_message_request: AnthropicMessagesRequest
     ) -> ChatCompletionRequest:
@@ -636,6 +672,16 @@ class LiteLLMAnthropicMessagesAdapter:
                     if reasoning_effort:
                         new_kwargs["reasoning_effort"] = reasoning_effort
 
+        ## CONVERT OUTPUT_FORMAT to RESPONSE_FORMAT
+        if "output_format" in anthropic_message_request:
+            output_format = anthropic_message_request["output_format"]
+            if output_format:
+                response_format = self.translate_anthropic_output_format_to_openai(
+                    output_format=output_format
+                )
+                if response_format:
+                    new_kwargs["response_format"] = response_format
+
         translatable_params = self.translatable_anthropic_params()
         for k, v in anthropic_message_request.items():
             if k not in translatable_params:  # pass remaining params as is
diff --git a/tests/pass_through_unit_tests/messages_api_structured_output/base_anthropic_messages_structured_output_test.py b/tests/pass_through_unit_tests/messages_api_structured_output/base_anthropic_messages_structured_output_test.py
index 9346345eef6..b0a8cf8b96f 100644
--- a/tests/pass_through_unit_tests/messages_api_structured_output/base_anthropic_messages_structured_output_test.py
+++ b/tests/pass_through_unit_tests/messages_api_structured_output/base_anthropic_messages_structured_output_test.py
@@ -107,14 +107,26 @@ class BaseAnthropicMessagesStructuredOutputTest(ABC):
 
         print(f"Response: {response}")
 
-        # Validate response structure
-        assert "content" in response
-        assert len(response["content"]) > 0
+        # Validate response structure - handle both dict and object responses
+        if isinstance(response, dict):
+            assert "content" in response
+            content_list = response["content"]
+        else:
+            assert hasattr(response, "content")
+            content_list = response.content
 
-        content = response["content"][0]
-        assert "text" in content
+        assert len(content_list) > 0
+
+        content = content_list[0]
+        
+        # Handle both dict and object content blocks
+        if isinstance(content, dict):
+            assert "text" in content
+            response_text = content["text"]
+        else:
+            assert hasattr(content, "text")
+            response_text = content.text
 
-        response_text = content["text"]
         print(f"Response text: {response_text}")
 
         # The response should be valid JSON