diff --git a/homeassistant/components/twitch/sensor.py b/homeassistant/components/twitch/sensor.py
index bcd9e95a1ae..a6e2f4e04af 100644
--- a/homeassistant/components/twitch/sensor.py
+++ b/homeassistant/components/twitch/sensor.py
@@ -28,6 +28,7 @@ ATTR_FOLLOW = "following"
 ATTR_FOLLOW_SINCE = "following_since"
 ATTR_FOLLOWING = "followers"
 ATTR_VIEWS = "views"
+ATTR_STARTED_AT = "started_at"
 
 STATE_OFFLINE = "offline"
 STATE_STREAMING = "streaming"
@@ -104,6 +105,7 @@ class TwitchSensor(SensorEntity):
             self._attr_native_value = STATE_STREAMING
             self._attr_extra_state_attributes[ATTR_GAME] = stream.game_name
             self._attr_extra_state_attributes[ATTR_TITLE] = stream.title
+            self._attr_extra_state_attributes[ATTR_STARTED_AT] = stream.started_at
             self._attr_entity_picture = stream.thumbnail_url
             if self._attr_entity_picture is not None:
                 self._attr_entity_picture = self._attr_entity_picture.format(
@@ -114,6 +116,7 @@ class TwitchSensor(SensorEntity):
             self._attr_native_value = STATE_OFFLINE
             self._attr_extra_state_attributes[ATTR_GAME] = None
             self._attr_extra_state_attributes[ATTR_TITLE] = None
+            self._attr_extra_state_attributes[ATTR_STARTED_AT] = None
             self._attr_entity_picture = self._channel.profile_image_url
 
     async def _async_add_user_attributes(self) -> None:
diff --git a/tests/components/twitch/fixtures/get_streams.json b/tests/components/twitch/fixtures/get_streams.json
index 3714d97aaef..53330c9c82e 100644
--- a/tests/components/twitch/fixtures/get_streams.json
+++ b/tests/components/twitch/fixtures/get_streams.json
@@ -2,6 +2,7 @@
   {
     "game_name": "Good game",
     "title": "Title",
-    "thumbnail_url": "stream-medium.png"
+    "thumbnail_url": "stream-medium.png",
+    "started_at": "2021-03-10T03:18:11Z"
   }
 ]
diff --git a/tests/components/twitch/test_sensor.py b/tests/components/twitch/test_sensor.py
index e5cddf8e192..8ce146adf07 100644
--- a/tests/components/twitch/test_sensor.py
+++ b/tests/components/twitch/test_sensor.py
@@ -3,6 +3,7 @@
 from datetime import datetime
 from unittest.mock import AsyncMock
 
+from dateutil.tz import tzutc
 from twitchAPI.object.api import FollowedChannel, Stream, UserSubscription
 from twitchAPI.type import TwitchResourceNotFound
 
@@ -41,6 +42,9 @@ async def test_streaming(
     assert sensor_state.attributes["entity_picture"] == "stream-medium.png"
     assert sensor_state.attributes["game"] == "Good game"
     assert sensor_state.attributes["title"] == "Title"
+    assert sensor_state.attributes["started_at"] == datetime(
+        year=2021, month=3, day=10, hour=3, minute=18, second=11, tzinfo=tzutc()
+    )
 
 
 async def test_oauth_without_sub_and_follow(