diff --git a/src/corelib/plugin/quuid.h b/src/corelib/plugin/quuid.h
index 299ce76d7b4..ddd24eb6786 100644
--- a/src/corelib/plugin/quuid.h
+++ b/src/corelib/plugin/quuid.h
@@ -55,7 +55,7 @@ public:
         Id128           = 3
     };
 
-    union Id128Bytes {
+    union alignas(16) Id128Bytes {
         quint8 data[16];
         quint16 data16[8];
         quint32 data32[4];