diff --git a/homeassistant/helpers/entity.py b/homeassistant/helpers/entity.py
index 9640901ae7a..023922a5814 100644
--- a/homeassistant/helpers/entity.py
+++ b/homeassistant/helpers/entity.py
@@ -249,6 +249,10 @@ class Entity(ABC):
     # If we reported this entity is updated while disabled
     _disabled_reported = False
 
+    # If we reported this entity is using async_update_ha_state, while
+    # it should be using async_write_ha_state.
+    _async_update_ha_state_reported = False
+
     # Protect for multiple updates
     _update_staged = False
 
@@ -552,6 +556,20 @@ class Entity(ABC):
                 _LOGGER.exception("Update for %s fails", self.entity_id)
                 return
 
+        if not self._async_update_ha_state_reported:
+            report_issue = self._suggest_report_issue()
+            _LOGGER.warning(
+                (
+                    "Entity %s (%s) is using self.async_update_ha_state(), without"
+                    " enabling force_update. Instead it should use"
+                    " self.async_write_ha_state(), please %s"
+                ),
+                self.entity_id,
+                type(self),
+                report_issue,
+            )
+            self._async_update_ha_state_reported = True
+
         self._async_write_ha_state()
 
     @callback
diff --git a/tests/helpers/test_entity.py b/tests/helpers/test_entity.py
index 17cfadca015..24bed13ef44 100644
--- a/tests/helpers/test_entity.py
+++ b/tests/helpers/test_entity.py
@@ -986,3 +986,20 @@ async def test_repr_using_stringify_state() -> None:
 
     entity = MyEntity(entity_id="test.test", available=False)
     assert str(entity) == "<entity test.test=unavailable>"
+
+
+async def test_warn_using_async_update_ha_state(
+    hass: HomeAssistant, caplog: pytest.LogCaptureFixture
+) -> None:
+    """Test we warn once when using async_update_ha_state without force_update."""
+    ent = entity.Entity()
+    ent.hass = hass
+    ent.entity_id = "hello.world"
+
+    caplog.clear()
+    await ent.async_update_ha_state()
+    assert "is using self.async_update_ha_state()" in caplog.text
+
+    caplog.clear()
+    await ent.async_update_ha_state()
+    assert "is using self.async_update_ha_state()" not in caplog.text