diff --git a/src/scripting/workspace_wrapper.cpp b/src/scripting/workspace_wrapper.cpp
index e54977a6ed..9544fa3981 100644
--- a/src/scripting/workspace_wrapper.cpp
+++ b/src/scripting/workspace_wrapper.cpp
@@ -397,13 +397,21 @@ QQmlListProperty<KWin::AbstractClient> DeclarativeScriptWorkspaceWrapper::client
     return QQmlListProperty<KWin::AbstractClient>(this, nullptr, &DeclarativeScriptWorkspaceWrapper::countClientList, &DeclarativeScriptWorkspaceWrapper::atClientList);
 }
 
+#if QT_VERSION < QT_VERSION_CHECK(6, 0, 0)
 int DeclarativeScriptWorkspaceWrapper::countClientList(QQmlListProperty<KWin::AbstractClient> *clients)
+#else
+qsizetype DeclarativeScriptWorkspaceWrapper::countClientList(QQmlListProperty<KWin::AbstractClient> *clients)
+#endif
 {
     Q_UNUSED(clients)
     return workspace()->allClientList().size();
 }
 
+#if QT_VERSION < QT_VERSION_CHECK(6, 0, 0)
 KWin::AbstractClient *DeclarativeScriptWorkspaceWrapper::atClientList(QQmlListProperty<KWin::AbstractClient> *clients, int index)
+#else
+KWin::AbstractClient *DeclarativeScriptWorkspaceWrapper::atClientList(QQmlListProperty<KWin::AbstractClient> *clients, qsizetype index)
+#endif
 {
     Q_UNUSED(clients)
     return workspace()->allClientList().at(index);
diff --git a/src/scripting/workspace_wrapper.h b/src/scripting/workspace_wrapper.h
index f85eeffb4f..6b8521cbc6 100644
--- a/src/scripting/workspace_wrapper.h
+++ b/src/scripting/workspace_wrapper.h
@@ -429,8 +429,13 @@ class DeclarativeScriptWorkspaceWrapper : public WorkspaceWrapper
     Q_PROPERTY(QQmlListProperty<KWin::AbstractClient> clients READ clients)
 public:
     QQmlListProperty<KWin::AbstractClient> clients();
+#if QT_VERSION < QT_VERSION_CHECK(6, 0, 0)
     static int countClientList(QQmlListProperty<KWin::AbstractClient> *clients);
     static KWin::AbstractClient *atClientList(QQmlListProperty<KWin::AbstractClient> *clients, int index);
+#else
+    static qsizetype countClientList(QQmlListProperty<KWin::AbstractClient> *clients);
+    static KWin::AbstractClient *atClientList(QQmlListProperty<KWin::AbstractClient> *clients, qsizetype index);
+#endif
 
     explicit DeclarativeScriptWorkspaceWrapper(QObject* parent = nullptr);
 };