diff --git a/src/google/adk/runners.py b/src/google/adk/runners.py
index 64343302fe..508c00d73d 100644
--- a/src/google/adk/runners.py
+++ b/src/google/adk/runners.py
@@ -926,6 +926,7 @@ async def run_live(
       session_id: Optional[str] = None,
       live_request_queue: LiveRequestQueue,
       run_config: Optional[RunConfig] = None,
+      state_delta: Optional[dict[str, Any]] = None,
       session: Optional[Session] = None,
   ) -> AsyncGenerator[Event, None]:
     """Runs the agent in live mode (experimental feature).
@@ -966,6 +967,7 @@ async def run_live(
           None.
         live_request_queue: The queue for live requests.
         run_config: The run config for the agent.
+        state_delta: Optional state changes to apply to the session.
         session: The session to use. This parameter is deprecated, please use
           `user_id` and `session_id` instead.
 
@@ -1009,6 +1011,16 @@ async def run_live(
         run_config=run_config,
     )
 
+    # Apply state_delta if provided
+    if state_delta:
+      state_event = Event(
+          invocation_id=invocation_context.invocation_id,
+          author='user',
+          actions=EventActions(state_delta=state_delta),
+      )
+      _apply_run_config_custom_metadata(state_event, run_config)
+      await self.session_service.append_event(session=session, event=state_event)
+
     root_agent = self.agent
     invocation_context.agent = self._find_agent_to_run(session, root_agent)
 
diff --git a/tests/unittests/test_runners.py b/tests/unittests/test_runners.py
index c876bff53a..a5f5833d74 100644
--- a/tests/unittests/test_runners.py
+++ b/tests/unittests/test_runners.py
@@ -442,6 +442,50 @@ async def _run_live_impl(
   assert "non_streaming_tool" not in active_tools
 
 
+@pytest.mark.asyncio
+async def test_run_live_state_delta_applied_to_session():
+  """run_live should apply state_delta to the session at the start."""
+  session_service = InMemorySessionService()
+  artifact_service = InMemoryArtifactService()
+  runner = Runner(
+      app_name="run_live_app",
+      agent=MockLiveAgent("live_agent"),
+      session_service=session_service,
+      artifact_service=artifact_service,
+      auto_create_session=True,
+  )
+
+  live_queue = LiveRequestQueue()
+  state_delta = {"useCase": "voice_assistant"}
+
+  agen = runner.run_live(
+      user_id="user",
+      session_id="test_session",
+      live_request_queue=live_queue,
+      state_delta=state_delta,
+  )
+
+  event = await agen.__anext__()
+  await agen.aclose()
+
+  assert event.author == "live_agent"
+
+  # Verify state_delta was applied to the session
+  session = await session_service.get_session(
+      app_name="run_live_app", user_id="user", session_id="test_session"
+  )
+  assert session is not None
+  assert session.state.get("useCase") == "voice_assistant"
+
+  # Verify the state_delta event was appended to the session
+  state_delta_events = [
+      e for e in session.events
+      if e.actions.state_delta and e.author == "user"
+  ]
+  assert len(state_delta_events) == 1
+  assert state_delta_events[0].actions.state_delta == state_delta
+
+
 @pytest.mark.asyncio
 async def test_runner_allows_nested_agent_directories(tmp_path, monkeypatch):
   project_root = tmp_path / "workspace"