diff --git a/src/gui/util/qdesktopservices.cpp b/src/gui/util/qdesktopservices.cpp
index 7a728cf692..1e77dcb3ae 100644
--- a/src/gui/util/qdesktopservices.cpp
+++ b/src/gui/util/qdesktopservices.cpp
@@ -54,6 +54,8 @@
 #include <qpa/qplatformintegration.h>
 #include <qdir.h>
 
+#include <QtCore/private/qlocking_p.h>
+
 QT_BEGIN_NAMESPACE
 
 class QOpenUrlHandlerRegistry : public QObject
@@ -81,6 +83,7 @@ Q_GLOBAL_STATIC(QOpenUrlHandlerRegistry, handlerRegistry)
 
 void QOpenUrlHandlerRegistry::handlerDestroyed(QObject *handler)
 {
+    const auto lock = qt_scoped_lock(mutex);
     HandlerHash::Iterator it = handlers.begin();
     while (it != handlers.end()) {
         if (it->receiver == handler) {