diff --git a/src/corelib/tools/qmap.h b/src/corelib/tools/qmap.h
index afc4ca37c4..65b3ba55db 100644
--- a/src/corelib/tools/qmap.h
+++ b/src/corelib/tools/qmap.h
@@ -220,6 +220,8 @@ class QMap
     using MapData = QMapData<std::map<Key, T>>;
     QtPrivate::QExplicitlySharedDataPointerV2<MapData> d;
 
+    friend class QMultiMap<Key, T>;
+
 public:
     using key_type = Key;
     using mapped_type = T;
@@ -778,6 +780,35 @@ public:
         qSwap(d, other.d);
     }
 
+    explicit QMultiMap(const QMap<Key, T> &other)
+        : d(other.isEmpty() ? nullptr : new MapData)
+    {
+        if (d) {
+            Q_ASSERT(other.d);
+            d->m.insert(other.d->m.begin(),
+                        other.d->m.end());
+        }
+    }
+
+    explicit QMultiMap(QMap<Key, T> &&other)
+        : d(other.isEmpty() ? nullptr : new MapData)
+    {
+        if (d) {
+            Q_ASSERT(other.d);
+            if (other.d.isShared()) {
+                d->m.insert(other.d->m.begin(),
+                            other.d->m.end());
+            } else {
+#ifdef __cpp_lib_node_extract
+                d->m.merge(std::move(other.d->m));
+#else
+                d->m.insert(std::make_move_iterator(other.d->m.begin()),
+                            std::make_move_iterator(other.d->m.end()));
+#endif
+            }
+        }
+    }
+
     explicit QMultiMap(const std::multimap<Key, T> &other)
         : d(other.empty() ? nullptr : new MapData(other))
     {
diff --git a/src/corelib/tools/qmultimap.qdoc b/src/corelib/tools/qmultimap.qdoc
index 0de4a6c8fd..9db495db1e 100644
--- a/src/corelib/tools/qmultimap.qdoc
+++ b/src/corelib/tools/qmultimap.qdoc
@@ -214,6 +214,19 @@
     initializer list \a list.
 */
 
+/*! \fn template <class Key, class T> QMultiMap<Key, T>::QMultiMap(const QMap<Key, T> &other)
+    \since 6.0
+
+    Constructs a multi map as a copy of \a other.
+*/
+
+/*! \fn template <class Key, class T> QMultiMap<Key, T>::QMultiMap(QMap<Key, T> &&other)
+    \since 6.0
+
+    If \a other is shared, constructs a multi map as a copy of \a other.
+    Otherwise, constructs a multi map by moving the elements from \a other.
+*/
+
 /*! \fn template <class Key, class T> QMultiMap<Key, T>::QMultiMap(const std::multimap<Key, T> &other)
 
     Constructs a copy of \a other.