diff --git a/src/helper/device_handler_base.py b/src/helper/device_handler_base.py
index 97a3018..7c674ed 100644
--- a/src/helper/device_handler_base.py
+++ b/src/helper/device_handler_base.py
@@ -1,5 +1,6 @@
 """Shared base class for all Hive device handlers."""
 
+import asyncio
 import logging
 from typing import Any
 
@@ -39,16 +40,24 @@ async def _execute_state_change(self, device: Device, **state_kwargs) -> bool:
             return False
         await self.session.hive_refresh_tokens()
         data = self.session.data.products[device.hive_id]
-        resp = await self.session.api.set_state(
-            data["type"], device.hive_id, **state_kwargs
-        )
-        if resp["original"] == HTTP_OK:
+        try:
+            resp = await self.session.api.set_state(
+                data["type"], device.hive_id, **state_kwargs
+            )
+        except asyncio.TimeoutError:
+            # Honour the documented False-on-failure contract so one slow
+            # device doesn't abort a multi-entity service call.
+            _LOGGER.warning(
+                "_execute_state_change - set_state timed out for %s", device.ha_name
+            )
+            return False
+        if resp.get("original") == HTTP_OK:
             await self.session.get_devices(device.hive_id)
             return True
         _LOGGER.error(
             "_execute_state_change - set_state failed for %s: HTTP %s",
             device.ha_name,
-            resp["original"],
+            resp.get("original"),
         )
         return False
 
diff --git a/tests/unit/test_base_handler.py b/tests/unit/test_base_handler.py
index 5720035..fcb6de9 100644
--- a/tests/unit/test_base_handler.py
+++ b/tests/unit/test_base_handler.py
@@ -2,9 +2,9 @@
 
 # pylint: disable=protected-access,too-few-public-methods,attribute-defined-outside-init
 
+import asyncio
 from unittest.mock import AsyncMock, MagicMock
 
-import pytest
 from apyhiveapi.helper.device_handler_base import BaseDeviceHandler
 from apyhiveapi.helper.hivedataclasses import Device
 from apyhiveapi.helper.map import Map
@@ -167,11 +167,20 @@ async def test_non_200_returns_false(self):
         assert result is False
         session.get_devices.assert_not_called()
 
-    async def test_malformed_set_state_response_raises_key_error(self):
-        """KeyError propagates when set_state response is missing 'original' key."""
+    async def test_malformed_set_state_response_returns_false(self):
+        """Returns False when set_state response is missing 'original' key."""
         session = _make_session({"prod-1": {"type": "heating"}})
         session.api.set_state = AsyncMock(return_value={"parsed": {}})
         h = _make_handler(session)
         d = _make_device()
-        with pytest.raises(KeyError):
-            await h._execute_state_change(d, mode="MANUAL")
+        assert await h._execute_state_change(d, mode="MANUAL") is False
+        session.get_devices.assert_not_called()
+
+    async def test_set_state_timeout_returns_false(self):
+        """Returns False instead of raising when set_state times out."""
+        session = _make_session({"prod-1": {"type": "heating"}})
+        session.api.set_state = AsyncMock(side_effect=asyncio.TimeoutError)
+        h = _make_handler(session)
+        d = _make_device()
+        assert await h._execute_state_change(d, mode="MANUAL") is False
+        session.get_devices.assert_not_called()