diff --git a/homeassistant/components/intent/timers.py b/homeassistant/components/intent/timers.py
index 3b7cf8813a9..0f7417f41b5 100644
--- a/homeassistant/components/intent/timers.py
+++ b/homeassistant/components/intent/timers.py
@@ -292,7 +292,8 @@ class TimerManager:
 
         timer.cancel()
 
-        self.handlers[timer.device_id](TimerEventType.CANCELLED, timer)
+        if timer.device_id in self.handlers:
+            self.handlers[timer.device_id](TimerEventType.CANCELLED, timer)
         _LOGGER.debug(
             "Timer cancelled: id=%s, name=%s, seconds_left=%s, device_id=%s",
             timer_id,
@@ -320,7 +321,8 @@ class TimerManager:
                 name=f"Timer {timer_id}",
             )
 
-        self.handlers[timer.device_id](TimerEventType.UPDATED, timer)
+        if timer.device_id in self.handlers:
+            self.handlers[timer.device_id](TimerEventType.UPDATED, timer)
 
         if seconds > 0:
             log_verb = "increased"
@@ -357,7 +359,8 @@ class TimerManager:
         task = self.timer_tasks.pop(timer_id)
         task.cancel()
 
-        self.handlers[timer.device_id](TimerEventType.UPDATED, timer)
+        if timer.device_id in self.handlers:
+            self.handlers[timer.device_id](TimerEventType.UPDATED, timer)
         _LOGGER.debug(
             "Timer paused: id=%s, name=%s, seconds_left=%s, device_id=%s",
             timer_id,
@@ -382,7 +385,8 @@ class TimerManager:
             name=f"Timer {timer.id}",
         )
 
-        self.handlers[timer.device_id](TimerEventType.UPDATED, timer)
+        if timer.device_id in self.handlers:
+            self.handlers[timer.device_id](TimerEventType.UPDATED, timer)
         _LOGGER.debug(
             "Timer unpaused: id=%s, name=%s, seconds_left=%s, device_id=%s",
             timer_id,
@@ -397,7 +401,8 @@ class TimerManager:
 
         timer.finish()
 
-        self.handlers[timer.device_id](TimerEventType.FINISHED, timer)
+        if timer.device_id in self.handlers:
+            self.handlers[timer.device_id](TimerEventType.FINISHED, timer)
         _LOGGER.debug(
             "Timer finished: id=%s, name=%s, device_id=%s",
             timer_id,
diff --git a/tests/components/intent/test_timers.py b/tests/components/intent/test_timers.py
index d017713bb1d..1c4e38349d0 100644
--- a/tests/components/intent/test_timers.py
+++ b/tests/components/intent/test_timers.py
@@ -971,6 +971,36 @@ async def test_timers_not_supported(hass: HomeAssistant) -> None:
             language=hass.config.language,
         )
 
+    # Start a timer
+    @callback
+    def handle_timer(event_type: TimerEventType, timer: TimerInfo) -> None:
+        pass
+
+    device_id = "test_device"
+    unregister = timer_manager.register_handler(device_id, handle_timer)
+
+    timer_id = timer_manager.start_timer(
+        device_id,
+        hours=None,
+        minutes=5,
+        seconds=None,
+        language=hass.config.language,
+    )
+
+    # Unregister handler so device no longer "supports" timers
+    unregister()
+
+    # All operations on the timer should not crash
+    timer_manager.add_time(timer_id, 1)
+
+    timer_manager.remove_time(timer_id, 1)
+
+    timer_manager.pause_timer(timer_id)
+
+    timer_manager.unpause_timer(timer_id)
+
+    timer_manager.cancel_timer(timer_id)
+
 
 async def test_timer_status_with_names(hass: HomeAssistant, init_components) -> None:
     """Test getting the status of named timers."""