diff --git a/litellm/integrations/opentelemetry.py b/litellm/integrations/opentelemetry.py
index b6d91d0b76d..b26850657d3 100644
--- a/litellm/integrations/opentelemetry.py
+++ b/litellm/integrations/opentelemetry.py
@@ -1678,17 +1678,35 @@ class OpenTelemetry(CustomLogger):
                     value=safe_dumps(transformed_messages),
                 )
 
-            if kwargs.get("system_instructions"):
-                transformed_system_instructions = (
-                    self._transform_messages_to_otel_semantic_conventions(
-                        kwargs.get("system_instructions")
+            # Coalesce the different kwarg names that carry the system
+            # prompt depending on the call path:
+            #   - "system_instructions" — Vertex AI Gemini chat-completion
+            #   - "instructions"        — OpenAI Responses API
+            #   - "system"              — Anthropic Messages API
+            system_instructions = (
+                kwargs.get("system_instructions")
+                or kwargs.get("instructions")
+                or kwargs.get("system")
+            )
+            if system_instructions:
+                if isinstance(system_instructions, str):
+                    # Plain text system prompt — no transformation needed
+                    self.safe_set_attribute(
+                        span=span,
+                        key=SpanAttributes.GEN_AI_SYSTEM_INSTRUCTIONS.value,
+                        value=system_instructions,
+                    )
+                else:
+                    transformed_system_instructions = (
+                        self._transform_messages_to_otel_semantic_conventions(
+                            system_instructions
+                        )
+                    )
+                    self.safe_set_attribute(
+                        span=span,
+                        key=SpanAttributes.GEN_AI_SYSTEM_INSTRUCTIONS.value,
+                        value=safe_dumps(transformed_system_instructions),
                     )
-                )
-                self.safe_set_attribute(
-                    span=span,
-                    key=SpanAttributes.GEN_AI_SYSTEM_INSTRUCTIONS.value,
-                    value=safe_dumps(transformed_system_instructions),
-                )
 
             self.safe_set_attribute(
                 span=span,
@@ -1747,6 +1765,32 @@ class OpenTelemetry(CustomLogger):
                                         value=value,
                                     )
 
+                elif response_obj.get("output"):
+                    # Responses API: ResponsesAPIResponse has an "output"
+                    # list instead of "choices".  Each item with
+                    # type="message" contains a "content" list of
+                    # OutputText objects (type="output_text").
+                    output_messages = (
+                        self._transform_responses_api_output_to_otel(
+                            response_obj.get("output")
+                        )
+                    )
+                    if output_messages:
+                        self.safe_set_attribute(
+                            span=span,
+                            key=SpanAttributes.GEN_AI_OUTPUT_MESSAGES.value,
+                            value=safe_dumps(output_messages),
+                        )
+
+                    # Extract finish reason from ResponsesAPIResponse.status
+                    status = response_obj.get("status")
+                    if status:
+                        self.safe_set_attribute(
+                            span=span,
+                            key=SpanAttributes.GEN_AI_RESPONSE_FINISH_REASONS.value,
+                            value=safe_dumps([status]),
+                        )
+
         except Exception as e:
             self.handle_callback_failure(
                 callback_name=self.callback_name or "opentelemetry"
@@ -1842,6 +1886,53 @@ class OpenTelemetry(CustomLogger):
             transformed.append(transformed_msg)
         return transformed
 
+    def _transform_responses_api_output_to_otel(
+        self, output: List[dict]
+    ) -> List[dict]:
+        """
+        Transform Responses API output items into OTEL GenAI 1.38 format.
+
+        The Responses API returns output as a list of items, each with a
+        ``type`` field.  Message items (``type="message"``) contain a
+        ``content`` list of ``OutputText`` objects with ``type="output_text"``
+        and ``text`` fields.
+
+        This method converts them to the same ``{"role": ..., "parts": [...]}``
+        format used by ``_transform_choices_to_otel_semantic_conventions``.
+        """
+        transformed = []
+        for item in output:
+            if not isinstance(item, dict):
+                continue
+            if item.get("type") == "message":
+                role = item.get("role", "assistant")
+                parts = []
+                for content in item.get("content", []):
+                    if not isinstance(content, dict):
+                        continue
+                    if content.get("type") == "output_text":
+                        text = content.get("text", "")
+                        if text:
+                            parts.append({"type": "text", "content": text})
+                if parts:
+                    transformed.append({"role": role, "parts": parts})
+            elif item.get("type") == "function_call":
+                # Surface tool calls from Responses API output
+                tool_call = {
+                    "role": "assistant",
+                    "parts": [
+                        {
+                            "type": "tool_call",
+                            "name": item.get("name", ""),
+                            "arguments": item.get("arguments", ""),
+                        }
+                    ],
+                }
+                if item.get("call_id"):
+                    tool_call["parts"][0]["id"] = item["call_id"]
+                transformed.append(tool_call)
+        return transformed
+
     def set_raw_request_attributes(self, span: Span, kwargs, response_obj):
         try:
             # Only set provider-specific raw payload attributes on this span.