diff --git a/changelog/3720.fixed.md b/changelog/3720.fixed.md
new file mode 100644
index 000000000..c3cb69d34
--- /dev/null
+++ b/changelog/3720.fixed.md
@@ -0,0 +1 @@
+- Fixed Grok Realtime `session.updated` event parsing failure caused by the API returning prefixed voice names (e.g. `"human_Ara"` instead of `"Ara"`).
diff --git a/src/pipecat/services/grok/realtime/events.py b/src/pipecat/services/grok/realtime/events.py
index 4069ff927..1f89a92f7 100644
--- a/src/pipecat/services/grok/realtime/events.py
+++ b/src/pipecat/services/grok/realtime/events.py
@@ -216,7 +216,7 @@ class SessionProperties(BaseModel):
     model_config = ConfigDict(arbitrary_types_allowed=True)
 
     instructions: Optional[str] = None
-    voice: Optional[GrokVoice] = "Ara"
+    voice: Optional[GrokVoice | str] = "Ara"
     turn_detection: Optional[TurnDetection] = Field(
         default_factory=lambda: TurnDetection(type="server_vad")
     )