diff --git a/homeassistant/components/humidifier/intent.py b/homeassistant/components/humidifier/intent.py
index ee257cc7123..fafbb0a494a 100644
--- a/homeassistant/components/humidifier/intent.py
+++ b/homeassistant/components/humidifier/intent.py
@@ -41,8 +41,7 @@ class HumidityHandler(intent.IntentHandler):
         hass = intent_obj.hass
         slots = self.async_validate_slots(intent_obj.slots)
         state = hass.helpers.intent.async_match_state(
-            slots["name"]["value"],
-            [state for state in hass.states.async_all() if state.domain == DOMAIN],
+            slots["name"]["value"], hass.states.async_all(DOMAIN)
         )
 
         service_data = {ATTR_ENTITY_ID: state.entity_id}
@@ -87,7 +86,7 @@ class SetModeHandler(intent.IntentHandler):
         slots = self.async_validate_slots(intent_obj.slots)
         state = hass.helpers.intent.async_match_state(
             slots["name"]["value"],
-            [state for state in hass.states.async_all() if state.domain == DOMAIN],
+            hass.states.async_all(DOMAIN),
         )
 
         service_data = {ATTR_ENTITY_ID: state.entity_id}
diff --git a/homeassistant/components/light/intent.py b/homeassistant/components/light/intent.py
index 58f74d8a422..be9346cf85b 100644
--- a/homeassistant/components/light/intent.py
+++ b/homeassistant/components/light/intent.py
@@ -39,8 +39,7 @@ class SetIntentHandler(intent.IntentHandler):
         hass = intent_obj.hass
         slots = self.async_validate_slots(intent_obj.slots)
         state = hass.helpers.intent.async_match_state(
-            slots["name"]["value"],
-            [state for state in hass.states.async_all() if state.domain == DOMAIN],
+            slots["name"]["value"], hass.states.async_all(DOMAIN)
         )
 
         service_data = {ATTR_ENTITY_ID: state.entity_id}
diff --git a/homeassistant/components/owntracks/__init__.py b/homeassistant/components/owntracks/__init__.py
index cf034950154..24dc99de71c 100644
--- a/homeassistant/components/owntracks/__init__.py
+++ b/homeassistant/components/owntracks/__init__.py
@@ -183,10 +183,7 @@ async def handle_webhook(hass, webhook_id, request):
 
     response = []
 
-    for person in hass.states.async_all():
-        if person.domain != "person":
-            continue
-
+    for person in hass.states.async_all("person"):
         if "latitude" in person.attributes and "longitude" in person.attributes:
             response.append(
                 {
diff --git a/homeassistant/core.py b/homeassistant/core.py
index ad083f60574..8f3809bbd4c 100644
--- a/homeassistant/core.py
+++ b/homeassistant/core.py
@@ -918,17 +918,29 @@ class StateMachine:
             if state.domain in domain_filter
         ]
 
-    def all(self) -> List[State]:
+    def all(self, domain_filter: Optional[Union[str, Iterable]] = None) -> List[State]:
         """Create a list of all states."""
-        return run_callback_threadsafe(self._loop, self.async_all).result()
+        return run_callback_threadsafe(
+            self._loop, self.async_all, domain_filter
+        ).result()
 
     @callback
-    def async_all(self) -> List[State]:
-        """Create a list of all states.
+    def async_all(
+        self, domain_filter: Optional[Union[str, Iterable]] = None
+    ) -> List[State]:
+        """Create a list of all states matching the filter.
 
         This method must be run in the event loop.
         """
-        return list(self._states.values())
+        if domain_filter is None:
+            return list(self._states.values())
+
+        if isinstance(domain_filter, str):
+            domain_filter = (domain_filter.lower(),)
+
+        return [
+            state for state in self._states.values() if state.domain in domain_filter
+        ]
 
     def get(self, entity_id: str) -> Optional[State]:
         """Retrieve state of entity_id or None if not found.
diff --git a/homeassistant/helpers/template.py b/homeassistant/helpers/template.py
index eeb43fb8756..405d8588532 100644
--- a/homeassistant/helpers/template.py
+++ b/homeassistant/helpers/template.py
@@ -459,8 +459,7 @@ class DomainStates:
             sorted(
                 (
                     _wrap_state(self._hass, state)
-                    for state in self._hass.states.async_all()
-                    if state.domain == self._domain
+                    for state in self._hass.states.async_all(self._domain)
                 ),
                 key=lambda state: state.entity_id,
             )
diff --git a/tests/test_core.py b/tests/test_core.py
index 22f1e779061..f5de9c5f1a1 100644
--- a/tests/test_core.py
+++ b/tests/test_core.py
@@ -1454,3 +1454,26 @@ async def test_chained_logging_misses_log_timeout(hass, caplog):
     await hass.async_block_till_done()
 
     assert "_task_chain_" not in caplog.text
+
+
+async def test_async_all(hass):
+    """Test async_all."""
+
+    hass.states.async_set("switch.link", "on")
+    hass.states.async_set("light.bowl", "on")
+    hass.states.async_set("light.frog", "on")
+    hass.states.async_set("vacuum.floor", "on")
+
+    assert {state.entity_id for state in hass.states.async_all()} == {
+        "switch.link",
+        "light.bowl",
+        "light.frog",
+        "vacuum.floor",
+    }
+    assert {state.entity_id for state in hass.states.async_all("light")} == {
+        "light.bowl",
+        "light.frog",
+    }
+    assert {
+        state.entity_id for state in hass.states.async_all(["light", "switch"])
+    } == {"light.bowl", "light.frog", "switch.link"}