diff --git a/homeassistant/components/timer/__init__.py b/homeassistant/components/timer/__init__.py
index b0ade17b9c9..b472e94a5c3 100644
--- a/homeassistant/components/timer/__init__.py
+++ b/homeassistant/components/timer/__init__.py
@@ -389,13 +389,15 @@ class Timer(collection.CollectionEntity, RestoreEntity):
     @callback
     def async_finish(self) -> None:
         """Reset and updates the states, fire finished event."""
-        if self._state != STATUS_ACTIVE or self._end is None:
+        if self._state == STATUS_IDLE:
             return
 
         if self._listener:
             self._listener()
             self._listener = None
         end = self._end
+        if end is None:
+            end = dt_util.utcnow().replace(microsecond=0)
         self._state = STATUS_IDLE
         self._end = None
         self._remaining = None
diff --git a/tests/components/timer/test_init.py b/tests/components/timer/test_init.py
index 95baa07eaa9..3e5ecc58b5a 100644
--- a/tests/components/timer/test_init.py
+++ b/tests/components/timer/test_init.py
@@ -208,6 +208,12 @@ async def test_methods_and_events(hass: HomeAssistant) -> None:
             "event": EVENT_TIMER_FINISHED,
             "data": {},
         },
+        {
+            "call": SERVICE_FINISH,
+            "state": STATUS_IDLE,
+            "event": None,
+            "data": {},
+        },
         {
             "call": SERVICE_START,
             "state": STATUS_ACTIVE,
@@ -244,6 +250,18 @@ async def test_methods_and_events(hass: HomeAssistant) -> None:
             "event": EVENT_TIMER_RESTARTED,
             "data": {},
         },
+        {
+            "call": SERVICE_PAUSE,
+            "state": STATUS_PAUSED,
+            "event": EVENT_TIMER_PAUSED,
+            "data": {},
+        },
+        {
+            "call": SERVICE_FINISH,
+            "state": STATUS_IDLE,
+            "event": EVENT_TIMER_FINISHED,
+            "data": {},
+        },
     ]
 
     expected_events = 0