diff --git a/src/corelib/global/qtclasshelpermacros.h b/src/corelib/global/qtclasshelpermacros.h
index 0b7f943ea73..952d3827507 100644
--- a/src/corelib/global/qtclasshelpermacros.h
+++ b/src/corelib/global/qtclasshelpermacros.h
@@ -141,10 +141,55 @@ namespace QtPrivate {
    where 'type' is the name of the type to specialize.  NOTE: shared
    types must define a member-swap, and be defined in the same
    namespace as Qt for this to work.
+
+   For types defined in a namespace within QT_NAMESPACE, use
+   Q_DECLARE_SHARED_NS/_EXT instead. The _NS macro needs to be placed
+   inside the nested namespace:
+
+     namespace ns {
+     // ~~~ type defined here ~~~
+     Q_DECLARE_SHARED_NS(ns, type)
+     }
+
+   while the _NS_EXT macro goes into the QT_NAMESPACE, outside any
+   nested namespaces:
+
+     namespace ns {
+     // ~~~ type defined here ~~~
+     }
+     Q_DECLARE_SHARED_NS_EXT(ns, type)
+
+   The latter then also works for more deeply-nested namespaces:
+
+     Q_DECLARE_SHARED_NS_EXT(ns1::ns2, type)
+
+   Q_DECLARE_SHARED_NS does, too, if all namespaces were opened in one statement:
+
+     namespace ns1::ns2 {
+     Q_DECLARE_SHARED_NS(ns1::ns2, type);
+     }
 */
 
 #define Q_DECLARE_SHARED(TYPE) \
+QT_DECLARE_ADL_SWAP(TYPE) \
 Q_DECLARE_TYPEINFO(TYPE, Q_RELOCATABLE_TYPE); \
+/* end */
+
+#define Q_DECLARE_SHARED_NS(NS, TYPE) \
+QT_DECLARE_ADL_SWAP(TYPE) \
+} /* namespace NS */ \
+Q_DECLARE_TYPEINFO(NS :: TYPE, Q_RELOCATABLE_TYPE); \
+namespace NS { \
+/* end */
+
+#define Q_DECLARE_SHARED_NS_EXT(NS, TYPE) \
+namespace NS { \
+QT_DECLARE_ADL_SWAP(TYPE) \
+} /* namespace NS */ \
+Q_DECLARE_TYPEINFO(NS :: TYPE, Q_RELOCATABLE_TYPE); \
+/* end */
+
+#define QT_DECLARE_ADL_SWAP(TYPE) \
 inline void swap(TYPE &value1, TYPE &value2) \
     noexcept(noexcept(value1.swap(value2))) \
 { value1.swap(value2); }
diff --git a/tests/auto/corelib/global/qglobal/tst_qglobal.cpp b/tests/auto/corelib/global/qglobal/tst_qglobal.cpp
index e98bdacd44a..7dd027160ed 100644
--- a/tests/auto/corelib/global/qglobal/tst_qglobal.cpp
+++ b/tests/auto/corelib/global/qglobal/tst_qglobal.cpp
@@ -42,6 +42,27 @@ static_assert(!q_is_adl_swappable_v<NotQDeclareShared>);
 MAKE_CLASS(Terry); // R.I.P.
 Q_DECLARE_SHARED(Terry)
 
+namespace Discworld {
+MAKE_CLASS(Librarian);
+Q_DECLARE_SHARED_NS(Discworld, Librarian)
+MAKE_CLASS(Baggage);
+namespace AnkhMorpork {
+MAKE_CLASS(Vetinari);
+// Q_DECLARE_SHARED_NS only work on a single nesting level
+namespace CityWatch {
+MAKE_CLASS(Vimes);
+} // namespace CityWatch
+} // namespace AnkhMorpork
+} // namespace Discworld
+Q_DECLARE_SHARED_NS_EXT(Discworld, Baggage)
+Q_DECLARE_SHARED_NS_EXT(Discworld::AnkhMorpork, Vetinari)
+Q_DECLARE_SHARED_NS_EXT(Discworld::AnkhMorpork::CityWatch, Vimes)
+// but Q_DECLARE_SHARED_NS works if all namespaces are opened in one statement:
+namespace Discworld::AnkhMorpork {
+MAKE_CLASS(Leonardo);
+Q_DECLARE_SHARED_NS(Discworld::AnkhMorpork, Leonardo)
+} // namespace Discworld::AnkhMorpork
+
 #undef MAKE_CLASS
 
 QT_END_NAMESPACE
@@ -432,12 +453,22 @@ void tst_QGlobal::qDeclareSharedMarksTheTypeRelocatable()
 {
     static_assert(!QTypeInfo<QT_PREPEND_NAMESPACE(NotQDeclareShared)>::isRelocatable);
     static_assert( QTypeInfo<QT_PREPEND_NAMESPACE(Terry)>::isRelocatable);
+    static_assert( QTypeInfo<QT_PREPEND_NAMESPACE(Discworld::Librarian)>::isRelocatable);
+    static_assert( QTypeInfo<QT_PREPEND_NAMESPACE(Discworld::Baggage)>::isRelocatable);
+    static_assert( QTypeInfo<QT_PREPEND_NAMESPACE(Discworld::AnkhMorpork::Vetinari)>::isRelocatable);
+    static_assert( QTypeInfo<QT_PREPEND_NAMESPACE(Discworld::AnkhMorpork::Leonardo)>::isRelocatable);
+    static_assert( QTypeInfo<QT_PREPEND_NAMESPACE(Discworld::AnkhMorpork::CityWatch::Vimes)>::isRelocatable);
 }
 
 void tst_QGlobal::qDeclareSharedMakesTheTypeAdlSwappable()
 {
     static_assert(!q_is_adl_swappable_v<QT_PREPEND_NAMESPACE(NotQDeclareShared)>);
     static_assert( q_is_adl_swappable_v<QT_PREPEND_NAMESPACE(Terry)>);
+    static_assert( q_is_adl_swappable_v<QT_PREPEND_NAMESPACE(Discworld::Librarian)>);
+    static_assert( q_is_adl_swappable_v<QT_PREPEND_NAMESPACE(Discworld::Baggage)>);
+    static_assert( q_is_adl_swappable_v<QT_PREPEND_NAMESPACE(Discworld::AnkhMorpork::Vetinari)>);
+    static_assert( q_is_adl_swappable_v<QT_PREPEND_NAMESPACE(Discworld::AnkhMorpork::Leonardo)>);
+    static_assert( q_is_adl_swappable_v<QT_PREPEND_NAMESPACE(Discworld::AnkhMorpork::CityWatch::Vimes)>);
 
     #define CHECK(Class) do { \
         using C = QT_PREPEND_NAMESPACE(Class); \
@@ -451,6 +482,11 @@ void tst_QGlobal::qDeclareSharedMakesTheTypeAdlSwappable()
         QCOMPARE_EQ(rhs.s, "lhs"); \
     } while (false)
     CHECK(Terry);
+    CHECK(Discworld::Librarian);
+    CHECK(Discworld::Baggage);
+    CHECK(Discworld::AnkhMorpork::Vetinari);
+    CHECK(Discworld::AnkhMorpork::Leonardo);
+    CHECK(Discworld::AnkhMorpork::CityWatch::Vimes);
     #undef CHECK
 }