diff --git a/src/gtk/control.cpp b/src/gtk/control.cpp
index c418af212c..86528ec99d 100644
--- a/src/gtk/control.cpp
+++ b/src/gtk/control.cpp
@@ -320,7 +320,7 @@ wxControl::GetDefaultAttributesFromGTKWidget(GtkWidget* widget,
 // been recalculated and cached by us. We want GTK+ information.
 wxSize wxControl::GTKGetPreferredSize(GtkWidget* widget) const
 {
-    GtkRequisition req;
+    GtkRequisition req = { 0, 0 };
 #ifdef __WXGTK3__
     int w, h;
     gtk_widget_get_size_request(widget, &w, &h);