diff --git a/src/plugins/platforms/windows/qwindowsdialoghelpers.cpp b/src/plugins/platforms/windows/qwindowsdialoghelpers.cpp
index 5197bcc31d1..0ce0b0e2a75 100644
--- a/src/plugins/platforms/windows/qwindowsdialoghelpers.cpp
+++ b/src/plugins/platforms/windows/qwindowsdialoghelpers.cpp
@@ -4,7 +4,6 @@
 #define QT_NO_URL_CAST_FROM_STRING 1
 
 #include <QtCore/qt_windows.h>
-#include "qwindowscombase.h"
 #include "qwindowsdialoghelpers.h"
 
 #include "qwindowscontext.h"
@@ -33,6 +32,7 @@
 #include <QtCore/qtemporaryfile.h>
 #include <QtCore/private/qfunctions_win_p.h>
 #include <QtCore/private/qsystemerror_p.h>
+#include <QtCore/private/qcomobject_p.h>
 
 #include <algorithm>
 #include <vector>
@@ -423,7 +423,7 @@ inline void QWindowsFileDialogSharedData::fromOptions(const QSharedPointer<QFile
 
 class QWindowsNativeFileDialogBase;
 
-class QWindowsNativeFileDialogEventHandler : public QWindowsComBase<IFileDialogEvents>
+class QWindowsNativeFileDialogEventHandler : public QComObject<IFileDialogEvents>
 {
     Q_DISABLE_COPY_MOVE(QWindowsNativeFileDialogEventHandler)
 public:
diff --git a/src/plugins/platforms/windows/qwindowsdrag.cpp b/src/plugins/platforms/windows/qwindowsdrag.cpp
index e8ec8d24a2a..c6f55c35093 100644
--- a/src/plugins/platforms/windows/qwindowsdrag.cpp
+++ b/src/plugins/platforms/windows/qwindowsdrag.cpp
@@ -29,6 +29,7 @@
 #include <QtCore/qbuffer.h>
 #include <QtCore/qpoint.h>
 #include <QtCore/qpointer.h>
+#include <QtCore/private/qcomobject_p.h>
 
 #include <shlobj.h>
 
@@ -168,7 +169,7 @@ static Qt::MouseButtons lastButtons = Qt::NoButton;
     \internal
 */
 
-class QWindowsOleDropSource : public QWindowsComBase<IDropSource>
+class QWindowsOleDropSource : public QComObject<IDropSource>
 {
 public:
     enum Mode {
diff --git a/src/plugins/platforms/windows/qwindowsdrag.h b/src/plugins/platforms/windows/qwindowsdrag.h
index 92abda295fa..a2d0e54044b 100644
--- a/src/plugins/platforms/windows/qwindowsdrag.h
+++ b/src/plugins/platforms/windows/qwindowsdrag.h
@@ -4,12 +4,12 @@
 #ifndef QWINDOWSDRAG_H
 #define QWINDOWSDRAG_H
 
-#include "qwindowscombase.h"
 #include "qwindowsinternalmimedata.h"
 
 #include <qpa/qplatformdrag.h>
 #include <QtGui/qpixmap.h>
 #include <QtGui/qdrag.h>
+#include <QtCore/private/qcomobject_p.h>
 
 struct IDropTargetHelper;
 
@@ -23,7 +23,7 @@ public:
     IDataObject *retrieveDataObject() const override;
 };
 
-class QWindowsOleDropTarget : public QWindowsComBase<IDropTarget>
+class QWindowsOleDropTarget : public QComObject<IDropTarget>
 {
 public:
     explicit QWindowsOleDropTarget(QWindow *w);
diff --git a/src/plugins/platforms/windows/qwindowsole.h b/src/plugins/platforms/windows/qwindowsole.h
index b687384684d..016f9dd04c0 100644
--- a/src/plugins/platforms/windows/qwindowsole.h
+++ b/src/plugins/platforms/windows/qwindowsole.h
@@ -4,12 +4,12 @@
 #ifndef QWINDOWSOLE_H
 #define QWINDOWSOLE_H
 
-#include "qwindowscombase.h"
 #include <QtCore/qt_windows.h>
 
 #include <QtCore/qlist.h>
 #include <QtCore/qmap.h>
 #include <QtCore/qpointer.h>
+#include <QtCore/private/qcomobject_p.h>
 
 #include <objidl.h>
 
@@ -18,7 +18,7 @@ QT_BEGIN_NAMESPACE
 class QMimeData;
 class QWindow;
 
-class QWindowsOleDataObject : public QWindowsComBase<IDataObject>
+class QWindowsOleDataObject : public QComObject<IDataObject>
 {
 public:
     explicit QWindowsOleDataObject(QMimeData *mimeData);
@@ -47,7 +47,7 @@ private:
     DWORD performedEffect = DROPEFFECT_NONE;
 };
 
-class QWindowsOleEnumFmtEtc : public QWindowsComBase<IEnumFORMATETC>
+class QWindowsOleEnumFmtEtc : public QComObject<IEnumFORMATETC>
 {
 public:
     explicit QWindowsOleEnumFmtEtc(const QList<FORMATETC> &fmtetcs);
diff --git a/src/plugins/platforms/windows/uiautomation/qwindowsuiabaseprovider.h b/src/plugins/platforms/windows/uiautomation/qwindowsuiabaseprovider.h
index c899b4096e8..445d71587ab 100644
--- a/src/plugins/platforms/windows/uiautomation/qwindowsuiabaseprovider.h
+++ b/src/plugins/platforms/windows/uiautomation/qwindowsuiabaseprovider.h
@@ -10,8 +10,8 @@
 #include <QtGui/qaccessible.h>
 #include <QtCore/qpointer.h>
 
-#include <qwindowscombase.h>
 #include <QtGui/private/qwindowsuiawrapper_p.h>
+#include <QtCore/private/qcomobject_p.h>
 
 QT_BEGIN_NAMESPACE
 
diff --git a/src/plugins/platforms/windows/uiautomation/qwindowsuiaexpandcollapseprovider.h b/src/plugins/platforms/windows/uiautomation/qwindowsuiaexpandcollapseprovider.h
index 49b37ba295c..b384eb521c1 100644
--- a/src/plugins/platforms/windows/uiautomation/qwindowsuiaexpandcollapseprovider.h
+++ b/src/plugins/platforms/windows/uiautomation/qwindowsuiaexpandcollapseprovider.h
@@ -13,7 +13,7 @@ QT_BEGIN_NAMESPACE
 
 // Implements the Expand/Collapse control pattern provider. Used for menu items with submenus.
 class QWindowsUiaExpandCollapseProvider : public QWindowsUiaBaseProvider,
-                                          public QWindowsComBase<IExpandCollapseProvider>
+                                          public QComObject<IExpandCollapseProvider>
 {
     Q_DISABLE_COPY_MOVE(QWindowsUiaExpandCollapseProvider)
 public:
diff --git a/src/plugins/platforms/windows/uiautomation/qwindowsuiagriditemprovider.h b/src/plugins/platforms/windows/uiautomation/qwindowsuiagriditemprovider.h
index b5016169668..289a8678690 100644
--- a/src/plugins/platforms/windows/uiautomation/qwindowsuiagriditemprovider.h
+++ b/src/plugins/platforms/windows/uiautomation/qwindowsuiagriditemprovider.h
@@ -13,7 +13,7 @@ QT_BEGIN_NAMESPACE
 
 // Implements the Grid Item control pattern provider. Used by items within a table/tree.
 class QWindowsUiaGridItemProvider : public QWindowsUiaBaseProvider,
-                                    public QWindowsComBase<IGridItemProvider>
+                                    public QComObject<IGridItemProvider>
 {
     Q_DISABLE_COPY_MOVE(QWindowsUiaGridItemProvider)
 public:
diff --git a/src/plugins/platforms/windows/uiautomation/qwindowsuiagridprovider.h b/src/plugins/platforms/windows/uiautomation/qwindowsuiagridprovider.h
index b905133f6bf..d33bbd04290 100644
--- a/src/plugins/platforms/windows/uiautomation/qwindowsuiagridprovider.h
+++ b/src/plugins/platforms/windows/uiautomation/qwindowsuiagridprovider.h
@@ -12,8 +12,7 @@
 QT_BEGIN_NAMESPACE
 
 // Implements the Grid control pattern provider. Used by tables/trees.
-class QWindowsUiaGridProvider : public QWindowsUiaBaseProvider,
-                                public QWindowsComBase<IGridProvider>
+class QWindowsUiaGridProvider : public QWindowsUiaBaseProvider, public QComObject<IGridProvider>
 {
     Q_DISABLE_COPY_MOVE(QWindowsUiaGridProvider)
 public:
diff --git a/src/plugins/platforms/windows/uiautomation/qwindowsuiainvokeprovider.h b/src/plugins/platforms/windows/uiautomation/qwindowsuiainvokeprovider.h
index eca7e730394..ec006c673ed 100644
--- a/src/plugins/platforms/windows/uiautomation/qwindowsuiainvokeprovider.h
+++ b/src/plugins/platforms/windows/uiautomation/qwindowsuiainvokeprovider.h
@@ -12,8 +12,7 @@
 QT_BEGIN_NAMESPACE
 
 // Implements the Invoke control pattern provider.
-class QWindowsUiaInvokeProvider : public QWindowsUiaBaseProvider,
-                                  public QWindowsComBase<IInvokeProvider>
+class QWindowsUiaInvokeProvider : public QWindowsUiaBaseProvider, public QComObject<IInvokeProvider>
 {
     Q_DISABLE_COPY_MOVE(QWindowsUiaInvokeProvider)
 public:
diff --git a/src/plugins/platforms/windows/uiautomation/qwindowsuiarangevalueprovider.h b/src/plugins/platforms/windows/uiautomation/qwindowsuiarangevalueprovider.h
index 3e06961a82d..ffb5ae155b0 100644
--- a/src/plugins/platforms/windows/uiautomation/qwindowsuiarangevalueprovider.h
+++ b/src/plugins/platforms/windows/uiautomation/qwindowsuiarangevalueprovider.h
@@ -13,7 +13,7 @@ QT_BEGIN_NAMESPACE
 
 // Implements the Range Value control pattern provider.
 class QWindowsUiaRangeValueProvider : public QWindowsUiaBaseProvider,
-                                      public QWindowsComBase<IRangeValueProvider>
+                                      public QComObject<IRangeValueProvider>
 {
     Q_DISABLE_COPY_MOVE(QWindowsUiaRangeValueProvider)
 public:
diff --git a/src/plugins/platforms/windows/uiautomation/qwindowsuiaselectionitemprovider.h b/src/plugins/platforms/windows/uiautomation/qwindowsuiaselectionitemprovider.h
index b510ae951c4..ee34fd9edd3 100644
--- a/src/plugins/platforms/windows/uiautomation/qwindowsuiaselectionitemprovider.h
+++ b/src/plugins/platforms/windows/uiautomation/qwindowsuiaselectionitemprovider.h
@@ -13,7 +13,7 @@ QT_BEGIN_NAMESPACE
 
 // Implements the Selection Item control pattern provider. Used for List items and radio buttons.
 class QWindowsUiaSelectionItemProvider : public QWindowsUiaBaseProvider,
-                                         public QWindowsComBase<ISelectionItemProvider>
+                                         public QComObject<ISelectionItemProvider>
 {
     Q_DISABLE_COPY_MOVE(QWindowsUiaSelectionItemProvider)
 public:
diff --git a/src/plugins/platforms/windows/uiautomation/qwindowsuiaselectionprovider.h b/src/plugins/platforms/windows/uiautomation/qwindowsuiaselectionprovider.h
index 8717e54ee76..7a899e4261e 100644
--- a/src/plugins/platforms/windows/uiautomation/qwindowsuiaselectionprovider.h
+++ b/src/plugins/platforms/windows/uiautomation/qwindowsuiaselectionprovider.h
@@ -11,27 +11,28 @@
 
 QT_BEGIN_NAMESPACE
 
+namespace QtPrivate {
+
+template <>
+struct QComObjectTraits<ISelectionProvider2>
+{
+    static constexpr bool isGuidOf(REFIID riid) noexcept
+    {
+        return QComObjectTraits<ISelectionProvider2, ISelectionProvider>::isGuidOf(riid);
+    }
+};
+
+} // namespace QtPrivate
+
 // Implements the Selection control pattern provider. Used for Lists.
 class QWindowsUiaSelectionProvider : public QWindowsUiaBaseProvider,
-                                     public QWindowsComBase<ISelectionProvider2>
+                                     public QComObject<ISelectionProvider2>
 {
     Q_DISABLE_COPY_MOVE(QWindowsUiaSelectionProvider)
 public:
     explicit QWindowsUiaSelectionProvider(QAccessible::Id id);
     virtual ~QWindowsUiaSelectionProvider();
 
-    // override to support ISelectionProvider and ISelectionProvider2 at the same time
-    HRESULT STDMETHODCALLTYPE QueryInterface(REFIID id, LPVOID *iface) override
-    {
-        HRESULT res = QWindowsComBase<ISelectionProvider2>::QueryInterface(id, iface);
-        // QWindowsComBase<ISelectionProvider2>::QueryInterface doesn't handle ISelectionProvider,
-        // from which ISelectionProvider2 inherits
-        if (res == E_NOINTERFACE)
-            res = qWindowsComQueryInterface<ISelectionProvider>(this, id, iface) ? S_OK : E_NOINTERFACE;
-
-        return res;
-    };
-
     // ISelectionProvider
     HRESULT STDMETHODCALLTYPE GetSelection(SAFEARRAY **pRetVal) override;
     HRESULT STDMETHODCALLTYPE get_CanSelectMultiple(BOOL *pRetVal) override;
diff --git a/src/plugins/platforms/windows/uiautomation/qwindowsuiatableitemprovider.h b/src/plugins/platforms/windows/uiautomation/qwindowsuiatableitemprovider.h
index 8aed1806719..3bb0e1027e3 100644
--- a/src/plugins/platforms/windows/uiautomation/qwindowsuiatableitemprovider.h
+++ b/src/plugins/platforms/windows/uiautomation/qwindowsuiatableitemprovider.h
@@ -13,7 +13,7 @@ QT_BEGIN_NAMESPACE
 
 // Implements the Table Item control pattern provider. Used by items within a table/tree.
 class QWindowsUiaTableItemProvider : public QWindowsUiaBaseProvider,
-                                     public QWindowsComBase<ITableItemProvider>
+                                     public QComObject<ITableItemProvider>
 {
     Q_DISABLE_COPY_MOVE(QWindowsUiaTableItemProvider)
 public:
diff --git a/src/plugins/platforms/windows/uiautomation/qwindowsuiatableprovider.h b/src/plugins/platforms/windows/uiautomation/qwindowsuiatableprovider.h
index 6454bb9441a..8beb11decf8 100644
--- a/src/plugins/platforms/windows/uiautomation/qwindowsuiatableprovider.h
+++ b/src/plugins/platforms/windows/uiautomation/qwindowsuiatableprovider.h
@@ -12,8 +12,7 @@
 QT_BEGIN_NAMESPACE
 
 // Implements the Table control pattern provider. Used by tables/trees.
-class QWindowsUiaTableProvider : public QWindowsUiaBaseProvider,
-                                 public QWindowsComBase<ITableProvider>
+class QWindowsUiaTableProvider : public QWindowsUiaBaseProvider, public QComObject<ITableProvider>
 {
     Q_DISABLE_COPY_MOVE(QWindowsUiaTableProvider)
 public:
diff --git a/src/plugins/platforms/windows/uiautomation/qwindowsuiatextprovider.cpp b/src/plugins/platforms/windows/uiautomation/qwindowsuiatextprovider.cpp
index ae108c604d1..172836232e1 100644
--- a/src/plugins/platforms/windows/uiautomation/qwindowsuiatextprovider.cpp
+++ b/src/plugins/platforms/windows/uiautomation/qwindowsuiatextprovider.cpp
@@ -26,20 +26,6 @@ QWindowsUiaTextProvider::~QWindowsUiaTextProvider()
 {
 }
 
-HRESULT STDMETHODCALLTYPE QWindowsUiaTextProvider::QueryInterface(REFIID iid, LPVOID *iface)
-{
-    qCDebug(lcQpaUiAutomation) << __FUNCTION__ << this;
-
-    if (!iface)
-        return E_INVALIDARG;
-    *iface = nullptr;
-
-    const bool result = qWindowsComQueryUnknownInterfaceMulti<ITextProvider>(this, iid, iface)
-        || qWindowsComQueryInterface<ITextProvider>(this, iid, iface)
-        || qWindowsComQueryInterface<ITextProvider2>(this, iid, iface);
-    return result ? S_OK : E_NOINTERFACE;
-}
-
 // Returns an array of providers for the selected text ranges.
 HRESULT STDMETHODCALLTYPE QWindowsUiaTextProvider::GetSelection(SAFEARRAY **pRetVal)
 {
diff --git a/src/plugins/platforms/windows/uiautomation/qwindowsuiatextprovider.h b/src/plugins/platforms/windows/uiautomation/qwindowsuiatextprovider.h
index 5e6d430f1a0..8f886510b4e 100644
--- a/src/plugins/platforms/windows/uiautomation/qwindowsuiatextprovider.h
+++ b/src/plugins/platforms/windows/uiautomation/qwindowsuiatextprovider.h
@@ -12,18 +12,27 @@
 
 QT_BEGIN_NAMESPACE
 
+namespace QtPrivate {
+
+template <>
+struct QComObjectTraits<ITextProvider2>
+{
+    static constexpr bool isGuidOf(REFIID riid) noexcept
+    {
+        return QComObjectTraits<ITextProvider2, ITextProvider>::isGuidOf(riid);
+    }
+};
+
+} // namespace QtPrivate
+
 // Implements the Text control pattern provider. Used for text controls.
-class QWindowsUiaTextProvider : public QWindowsUiaBaseProvider,
-                                public QWindowsComBase<ITextProvider2>
+class QWindowsUiaTextProvider : public QWindowsUiaBaseProvider, public QComObject<ITextProvider2>
 {
     Q_DISABLE_COPY_MOVE(QWindowsUiaTextProvider)
 public:
     explicit QWindowsUiaTextProvider(QAccessible::Id id);
     ~QWindowsUiaTextProvider();
 
-    // IUnknown overrides
-    HRESULT STDMETHODCALLTYPE QueryInterface(REFIID id, LPVOID *iface) override;
-
     // ITextProvider
     HRESULT STDMETHODCALLTYPE GetSelection(SAFEARRAY **pRetVal) override;
     HRESULT STDMETHODCALLTYPE GetVisibleRanges(SAFEARRAY **pRetVal) override;
diff --git a/src/plugins/platforms/windows/uiautomation/qwindowsuiatextrangeprovider.h b/src/plugins/platforms/windows/uiautomation/qwindowsuiatextrangeprovider.h
index d9a9c67ee05..a37429a6038 100644
--- a/src/plugins/platforms/windows/uiautomation/qwindowsuiatextrangeprovider.h
+++ b/src/plugins/platforms/windows/uiautomation/qwindowsuiatextrangeprovider.h
@@ -13,7 +13,7 @@ QT_BEGIN_NAMESPACE
 
 // Implements the Text Range control pattern provider. Used for text controls.
 class QWindowsUiaTextRangeProvider : public QWindowsUiaBaseProvider,
-                                     public QWindowsComBase<ITextRangeProvider>
+                                     public QComObject<ITextRangeProvider>
 {
     Q_DISABLE_COPY_MOVE(QWindowsUiaTextRangeProvider)
 public:
diff --git a/src/plugins/platforms/windows/uiautomation/qwindowsuiatoggleprovider.h b/src/plugins/platforms/windows/uiautomation/qwindowsuiatoggleprovider.h
index 742e26f6d6b..17150dfbe05 100644
--- a/src/plugins/platforms/windows/uiautomation/qwindowsuiatoggleprovider.h
+++ b/src/plugins/platforms/windows/uiautomation/qwindowsuiatoggleprovider.h
@@ -12,8 +12,7 @@
 QT_BEGIN_NAMESPACE
 
 // Implements the Toggle control pattern provider. Used for checkboxes.
-class QWindowsUiaToggleProvider : public QWindowsUiaBaseProvider,
-                                  public QWindowsComBase<IToggleProvider>
+class QWindowsUiaToggleProvider : public QWindowsUiaBaseProvider, public QComObject<IToggleProvider>
 {
     Q_DISABLE_COPY_MOVE(QWindowsUiaToggleProvider)
 public:
diff --git a/src/plugins/platforms/windows/uiautomation/qwindowsuiavalueprovider.h b/src/plugins/platforms/windows/uiautomation/qwindowsuiavalueprovider.h
index 2f52019d333..8c0a6b8ee71 100644
--- a/src/plugins/platforms/windows/uiautomation/qwindowsuiavalueprovider.h
+++ b/src/plugins/platforms/windows/uiautomation/qwindowsuiavalueprovider.h
@@ -13,8 +13,7 @@ QT_BEGIN_NAMESPACE
 
 // Implements the Value control pattern provider.
 // Supported for all controls that can return text(QAccessible::Value).
-class QWindowsUiaValueProvider : public QWindowsUiaBaseProvider,
-                                 public QWindowsComBase<IValueProvider>
+class QWindowsUiaValueProvider : public QWindowsUiaBaseProvider, public QComObject<IValueProvider>
 {
     Q_DISABLE_COPY_MOVE(QWindowsUiaValueProvider)
 public:
diff --git a/src/plugins/platforms/windows/uiautomation/qwindowsuiawindowprovider.h b/src/plugins/platforms/windows/uiautomation/qwindowsuiawindowprovider.h
index e277b3f5c5a..89a16552328 100644
--- a/src/plugins/platforms/windows/uiautomation/qwindowsuiawindowprovider.h
+++ b/src/plugins/platforms/windows/uiautomation/qwindowsuiawindowprovider.h
@@ -11,8 +11,7 @@
 
 QT_BEGIN_NAMESPACE
 
-class QWindowsUiaWindowProvider : public QWindowsUiaBaseProvider,
-                                  public QWindowsComBase<IWindowProvider>
+class QWindowsUiaWindowProvider : public QWindowsUiaBaseProvider, public QComObject<IWindowProvider>
 {
     Q_DISABLE_COPY(QWindowsUiaWindowProvider)
 public: