diff --git a/orientation_sensor.h b/orientation_sensor.h
index d9786a8f11..90c6c4c3a8 100644
--- a/orientation_sensor.h
+++ b/orientation_sensor.h
@@ -26,7 +26,6 @@ along with this program.  If not, see <http://www.gnu.org/licenses/>.
 #include <kwin_export.h>
 
 class QOrientationSensor;
-class OrientationSensorAdaptor;
 class KStatusNotifierItem;
 
 namespace KWin