diff --git a/src/corelib/itemmodels/qabstractitemmodel.cpp b/src/corelib/itemmodels/qabstractitemmodel.cpp
index 31a88e8fec2..a042dceca07 100644
--- a/src/corelib/itemmodels/qabstractitemmodel.cpp
+++ b/src/corelib/itemmodels/qabstractitemmodel.cpp
@@ -19,6 +19,8 @@
 #include <qdatetime.h>
 #include <qloggingcategory.h>
 
+#include <functional>
+
 #include <limits.h>
 
 QT_BEGIN_NAMESPACE
@@ -402,7 +404,7 @@ bool QPersistentModelIndex::operator<(const QPersistentModelIndex &other) const
     if (d && other.d)
         return d->index < other.d->index;
 
-    return d < other.d;
+    return std::less<>{}(d, other.d);
 }
 
 /*!