diff --git a/effects/effect_builtins.h b/effects/effect_builtins.h
index 7c706d91a3..b471cf077a 100644
--- a/effects/effect_builtins.h
+++ b/effects/effect_builtins.h
@@ -22,6 +22,7 @@ along with this program.  If not, see <http://www.gnu.org/licenses/>.
 #include <kwineffects_export.h>
 #include <QStringList>
 #include <QUrl>
+#include <functional>
 
 namespace KWin
 {
diff --git a/toplevel.h b/toplevel.h
index 2fce2c1060..c7492e9421 100644
--- a/toplevel.h
+++ b/toplevel.h
@@ -40,6 +40,8 @@ along with this program.  If not, see <http://www.gnu.org/licenses/>.
 #include <fixx11h.h>
 // system
 #include <assert.h>
+// c++
+#include <functional>
 
 namespace KWin
 {