diff --git a/src/corelib/kernel/qmetatype.cpp b/src/corelib/kernel/qmetatype.cpp
index 1c2665e53c0..95845b7a9da 100644
--- a/src/corelib/kernel/qmetatype.cpp
+++ b/src/corelib/kernel/qmetatype.cpp
@@ -2979,8 +2979,13 @@ bool QMetaType::hasRegisteredDataStreamOperators() const
    If this metatype represents an enumeration, this method returns a
    metatype of a numeric class of the same signedness and size as the
    enums underlying type.
-   If it represents a QFlags type, it returns QMetaType::Int.
+   If it represents a QFlags type, it returns a metatype of a numeric class
+   with the same signedness and size as that \l QFlags::Int type.
    In all other cases an invalid QMetaType is returned.
+
+   Do note the metatype is synthesized from size and signedness and may thus
+   not match the actual underlying type of the enum itself. That is, it will
+   never return the metatype for \c{char}, \c{long}, \c{unsigned long}.
  */
 QMetaType QMetaType::underlyingType() const
 {
diff --git a/src/corelib/kernel/qmetatype.h b/src/corelib/kernel/qmetatype.h
index f3dee0433b2..80d850ff7a6 100644
--- a/src/corelib/kernel/qmetatype.h
+++ b/src/corelib/kernel/qmetatype.h
@@ -1267,10 +1267,12 @@ namespace QtPrivate {
     template<typename T>
     inline constexpr bool IsQmlListType = false;
 
-    template<typename T, bool = std::is_enum<T>::value>
+    template<typename T, bool = std::is_enum<T>::value, bool = QtPrivate::IsQFlags<T>::value>
     constexpr bool IsUnsignedEnum = false;
-    template<typename T>
-    constexpr bool IsUnsignedEnum<T, true> = !std::is_signed_v<std::underlying_type_t<T>>;
+    template<typename T> constexpr bool IsUnsignedEnum<T, true, false> =
+            !std::is_signed_v<std::underlying_type_t<T>>;
+    template<typename T> constexpr bool IsUnsignedEnum<T, false, true> =
+            !std::is_signed_v<std::underlying_type_t<typename T::enum_type>>;
 
     template<typename T>
     struct QMetaTypeTypeFlags