diff --git a/homeassistant/components/fitbit/application_credentials.py b/homeassistant/components/fitbit/application_credentials.py
index caa47351f45..bbd7af09183 100644
--- a/homeassistant/components/fitbit/application_credentials.py
+++ b/homeassistant/components/fitbit/application_credentials.py
@@ -69,6 +69,8 @@ class FitbitOAuth2Implementation(AuthImplementation):
                 )
             if err.status == HTTPStatus.UNAUTHORIZED:
                 raise FitbitAuthException(f"Unauthorized error: {err}") from err
+            if err.status == HTTPStatus.BAD_REQUEST:
+                raise FitbitAuthException(f"Bad Request error: {err}") from err
             raise FitbitApiException(f"Server error response: {err}") from err
         except aiohttp.ClientError as err:
             raise FitbitApiException(f"Client connection error: {err}") from err
diff --git a/tests/components/fitbit/test_init.py b/tests/components/fitbit/test_init.py
index 3ed3695ff3d..74312348af1 100644
--- a/tests/components/fitbit/test_init.py
+++ b/tests/components/fitbit/test_init.py
@@ -106,7 +106,13 @@ async def test_token_refresh_success(
     )
 
 
-@pytest.mark.parametrize("token_expiration_time", [12345])
+@pytest.mark.parametrize(
+    ("token_expiration_time", "server_status"),
+    [
+        (12345, HTTPStatus.UNAUTHORIZED),
+        (12345, HTTPStatus.BAD_REQUEST),
+    ],
+)
 @pytest.mark.parametrize("closing", [True, False])
 async def test_token_requires_reauth(
     hass: HomeAssistant,
@@ -114,13 +120,14 @@ async def test_token_requires_reauth(
     config_entry: MockConfigEntry,
     aioclient_mock: AiohttpClientMocker,
     setup_credentials: None,
+    server_status: HTTPStatus,
     closing: bool,
 ) -> None:
     """Test where token is expired and the refresh attempt requires reauth."""
 
     aioclient_mock.post(
         OAUTH2_TOKEN,
-        status=HTTPStatus.UNAUTHORIZED,
+        status=server_status,
         closing=closing,
     )
 
diff --git a/tests/components/fitbit/test_sensor.py b/tests/components/fitbit/test_sensor.py
index 871088eae63..91aafd944b0 100644
--- a/tests/components/fitbit/test_sensor.py
+++ b/tests/components/fitbit/test_sensor.py
@@ -599,21 +599,25 @@ async def test_settings_scope_config_entry(
 
 
 @pytest.mark.parametrize(
-    ("scopes"),
-    [(["heartrate"])],
+    ("scopes", "server_status"),
+    [
+        (["heartrate"], HTTPStatus.INTERNAL_SERVER_ERROR),
+        (["heartrate"], HTTPStatus.BAD_REQUEST),
+    ],
 )
 async def test_sensor_update_failed(
     hass: HomeAssistant,
     setup_credentials: None,
     integration_setup: Callable[[], Awaitable[bool]],
     requests_mock: Mocker,
+    server_status: HTTPStatus,
 ) -> None:
     """Test a failed sensor update when talking to the API."""
 
     requests_mock.register_uri(
         "GET",
         TIMESERIES_API_URL_FORMAT.format(resource="activities/heart"),
-        status_code=HTTPStatus.INTERNAL_SERVER_ERROR,
+        status_code=server_status,
     )
 
     assert await integration_setup()