diff --git a/gtk/gtkapplication-dbus.c b/gtk/gtkapplication-dbus.c
index a1f6eb0c3a..409f5f570f 100644
--- a/gtk/gtkapplication-dbus.c
+++ b/gtk/gtkapplication-dbus.c
@@ -631,7 +631,7 @@ gtk_application_impl_dbus_inhibit (GtkApplicationImpl         *impl,
                                     g_variant_new ("(s@usu)",
                                                    dbus->application_id,
                                                    window ? gtk_application_impl_dbus_get_window_system_id (dbus, window) : g_variant_new_uint32 (0),
-                                                   reason,
+                                                   reason ? reason : "",
                                                    flags),
                                     G_DBUS_CALL_FLAGS_NONE,
                                     G_MAXINT,