diff --git a/homeassistant/components/homekit_controller/binary_sensor.py b/homeassistant/components/homekit_controller/binary_sensor.py
index 91c1c47d47e..5efd0915cb0 100644
--- a/homeassistant/components/homekit_controller/binary_sensor.py
+++ b/homeassistant/components/homekit_controller/binary_sensor.py
@@ -63,7 +63,7 @@ class HomeKitSmokeSensor(HomeKitEntity, BinarySensorEntity):
 class HomeKitCarbonMonoxideSensor(HomeKitEntity, BinarySensorEntity):
     """Representation of a Homekit BO sensor."""
 
-    _attr_device_class = BinarySensorDeviceClass.GAS
+    _attr_device_class = BinarySensorDeviceClass.CO
 
     def get_characteristic_types(self) -> list[str]:
         """Define the homekit characteristics the entity is tracking."""
diff --git a/tests/components/homekit_controller/test_binary_sensor.py b/tests/components/homekit_controller/test_binary_sensor.py
index d83beb07df3..ff9877b2e44 100644
--- a/tests/components/homekit_controller/test_binary_sensor.py
+++ b/tests/components/homekit_controller/test_binary_sensor.py
@@ -114,7 +114,7 @@ async def test_carbon_monoxide_sensor_read_state(hass, utcnow):
     state = await helper.poll_and_get_state()
     assert state.state == "on"
 
-    assert state.attributes["device_class"] == BinarySensorDeviceClass.GAS
+    assert state.attributes["device_class"] == BinarySensorDeviceClass.CO
 
 
 def create_occupancy_sensor_service(accessory):