diff --git a/changelog/4004.added.md b/changelog/4004.added.md
new file mode 100644
index 000000000..f0fd28767
--- /dev/null
+++ b/changelog/4004.added.md
@@ -0,0 +1 @@
+- Added optional `service` field to `ServiceUpdateSettingsFrame` (and its subclasses `LLMUpdateSettingsFrame`, `TTSUpdateSettingsFrame`, `STTUpdateSettingsFrame`) to target a specific service instance. When `service` is set, only the matching service applies the settings; others forward the frame unchanged. This enables updating a single service when multiple services of the same type exist in the pipeline.
diff --git a/src/pipecat/frames/frames.py b/src/pipecat/frames/frames.py
index 390eb93dd..f58dc957f 100644
--- a/src/pipecat/frames/frames.py
+++ b/src/pipecat/frames/frames.py
@@ -2154,10 +2154,15 @@ class ServiceUpdateSettingsFrame(ControlFrame, UninterruptibleFrame):
 
         delta: :class:`~pipecat.services.settings.ServiceSettings` delta-mode
             object describing the fields to change.
+
+        service: Optional target service instance. When provided, only that
+            service will apply the settings; other services will forward the
+            frame unchanged.
     """
 
     settings: Mapping[str, Any] = field(default_factory=dict)
     delta: Optional["ServiceSettings"] = None
+    service: Optional["FrameProcessor"] = None
 
 
 @dataclass
diff --git a/src/pipecat/services/llm_service.py b/src/pipecat/services/llm_service.py
index 7944f413a..a479fcfc6 100644
--- a/src/pipecat/services/llm_service.py
+++ b/src/pipecat/services/llm_service.py
@@ -403,7 +403,9 @@ class LLMService(UserTurnCompletionLLMServiceMixin, AIService):
         elif isinstance(frame, LLMConfigureOutputFrame):
             self._skip_tts = frame.skip_tts
         elif isinstance(frame, LLMUpdateSettingsFrame):
-            if frame.delta is not None:
+            if frame.service is not None and frame.service is not self:
+                await self.push_frame(frame, direction)
+            elif frame.delta is not None:
                 await self._update_settings(frame.delta)
             elif frame.settings:
                 # Backward-compatible path: convert legacy dict to settings object.
diff --git a/src/pipecat/services/stt_service.py b/src/pipecat/services/stt_service.py
index ebf007f6f..a16aa0eaa 100644
--- a/src/pipecat/services/stt_service.py
+++ b/src/pipecat/services/stt_service.py
@@ -357,7 +357,9 @@ class STTService(AIService):
             await self._handle_vad_user_stopped_speaking(frame)
             await self.push_frame(frame, direction)
         elif isinstance(frame, STTUpdateSettingsFrame):
-            if frame.delta is not None:
+            if frame.service is not None and frame.service is not self:
+                await self.push_frame(frame, direction)
+            elif frame.delta is not None:
                 await self._update_settings(frame.delta)
             elif frame.settings:
                 # Backward-compatible path: convert legacy dict to settings object.
diff --git a/src/pipecat/services/tts_service.py b/src/pipecat/services/tts_service.py
index da1bcaf87..a79156018 100644
--- a/src/pipecat/services/tts_service.py
+++ b/src/pipecat/services/tts_service.py
@@ -738,7 +738,9 @@ class TTSService(AIService):
             self._turn_context_id = saved_turn_context_id
             self._processing_text = processing_text
         elif isinstance(frame, TTSUpdateSettingsFrame):
-            if frame.delta is not None:
+            if frame.service is not None and frame.service is not self:
+                await self.push_frame(frame, direction)
+            elif frame.delta is not None:
                 await self._update_settings(frame.delta)
             elif frame.settings:
                 # Backward-compatible path: convert legacy dict to settings object.