diff --git a/src/corelib/tools/qtimezoneprivate.cpp b/src/corelib/tools/qtimezoneprivate.cpp
index ea8f6d1438..7b780ecf7d 100644
--- a/src/corelib/tools/qtimezoneprivate.cpp
+++ b/src/corelib/tools/qtimezoneprivate.cpp
@@ -136,7 +136,7 @@ QTimeZonePrivate::~QTimeZonePrivate()
 {
 }
 
-QTimeZonePrivate *QTimeZonePrivate::clone()
+QTimeZonePrivate *QTimeZonePrivate::clone() const
 {
     return new QTimeZonePrivate(*this);
 }
@@ -784,7 +784,7 @@ QUtcTimeZonePrivate::~QUtcTimeZonePrivate()
 {
 }
 
-QTimeZonePrivate *QUtcTimeZonePrivate::clone()
+QUtcTimeZonePrivate *QUtcTimeZonePrivate::clone() const
 {
     return new QUtcTimeZonePrivate(*this);
 }
diff --git a/src/corelib/tools/qtimezoneprivate_android.cpp b/src/corelib/tools/qtimezoneprivate_android.cpp
index e079fa0d63..c3f8c3e0d9 100644
--- a/src/corelib/tools/qtimezoneprivate_android.cpp
+++ b/src/corelib/tools/qtimezoneprivate_android.cpp
@@ -88,7 +88,7 @@ void QAndroidTimeZonePrivate::init(const QByteArray &ianaId)
         m_id = ianaId;
 }
 
-QTimeZonePrivate *QAndroidTimeZonePrivate::clone()
+QAndroidTimeZonePrivate *QAndroidTimeZonePrivate::clone() const
 {
     return new QAndroidTimeZonePrivate(*this);
 }
diff --git a/src/corelib/tools/qtimezoneprivate_icu.cpp b/src/corelib/tools/qtimezoneprivate_icu.cpp
index c088fe7694..887486f567 100644
--- a/src/corelib/tools/qtimezoneprivate_icu.cpp
+++ b/src/corelib/tools/qtimezoneprivate_icu.cpp
@@ -305,7 +305,7 @@ QIcuTimeZonePrivate::~QIcuTimeZonePrivate()
     ucal_close(m_ucal);
 }
 
-QTimeZonePrivate *QIcuTimeZonePrivate::clone()
+QIcuTimeZonePrivate *QIcuTimeZonePrivate::clone() const
 {
     return new QIcuTimeZonePrivate(*this);
 }
diff --git a/src/corelib/tools/qtimezoneprivate_mac.mm b/src/corelib/tools/qtimezoneprivate_mac.mm
index 0c2dbe6fef..4e9a432fbf 100644
--- a/src/corelib/tools/qtimezoneprivate_mac.mm
+++ b/src/corelib/tools/qtimezoneprivate_mac.mm
@@ -82,7 +82,7 @@ QMacTimeZonePrivate::~QMacTimeZonePrivate()
     [m_nstz release];
 }
 
-QTimeZonePrivate *QMacTimeZonePrivate::clone()
+QMacTimeZonePrivate *QMacTimeZonePrivate::clone() const
 {
     return new QMacTimeZonePrivate(*this);
 }
diff --git a/src/corelib/tools/qtimezoneprivate_p.h b/src/corelib/tools/qtimezoneprivate_p.h
index 158c547f6a..9985d0672c 100644
--- a/src/corelib/tools/qtimezoneprivate_p.h
+++ b/src/corelib/tools/qtimezoneprivate_p.h
@@ -92,7 +92,7 @@ public:
     QTimeZonePrivate(const QTimeZonePrivate &other);
     virtual ~QTimeZonePrivate();
 
-    virtual QTimeZonePrivate *clone();
+    virtual QTimeZonePrivate *clone() const;
 
     bool operator==(const QTimeZonePrivate &other) const;
     bool operator!=(const QTimeZonePrivate &other) const;
@@ -187,7 +187,7 @@ public:
     QUtcTimeZonePrivate(const QUtcTimeZonePrivate &other);
     virtual ~QUtcTimeZonePrivate();
 
-    QTimeZonePrivate *clone() Q_DECL_OVERRIDE;
+    QUtcTimeZonePrivate *clone() const override;
 
     Data data(qint64 forMSecsSinceEpoch) const Q_DECL_OVERRIDE;
 
@@ -234,7 +234,7 @@ public:
     QIcuTimeZonePrivate(const QIcuTimeZonePrivate &other);
     ~QIcuTimeZonePrivate();
 
-    QTimeZonePrivate *clone() Q_DECL_OVERRIDE;
+    QIcuTimeZonePrivate *clone() const override;
 
     QString displayName(QTimeZone::TimeType timeType, QTimeZone::NameType nameType,
                         const QLocale &locale) const Q_DECL_OVERRIDE;
@@ -295,7 +295,7 @@ public:
     QTzTimeZonePrivate(const QByteArray &ianaId);
     ~QTzTimeZonePrivate();
 
-    QTimeZonePrivate *clone() Q_DECL_OVERRIDE;
+    QTzTimeZonePrivate *clone() const override;
 
     QLocale::Country country() const Q_DECL_OVERRIDE;
     QString comment() const Q_DECL_OVERRIDE;
@@ -351,7 +351,7 @@ public:
     QMacTimeZonePrivate(const QMacTimeZonePrivate &other);
     ~QMacTimeZonePrivate();
 
-    QTimeZonePrivate *clone() Q_DECL_OVERRIDE;
+    QMacTimeZonePrivate *clone() const override;
 
     QString comment() const Q_DECL_OVERRIDE;
 
@@ -404,7 +404,7 @@ public:
     QWinTimeZonePrivate(const QWinTimeZonePrivate &other);
     ~QWinTimeZonePrivate();
 
-    QTimeZonePrivate *clone() Q_DECL_OVERRIDE;
+    QWinTimeZonePrivate *clone() const override;
 
     QString comment() const Q_DECL_OVERRIDE;
 
@@ -454,7 +454,7 @@ public:
     QAndroidTimeZonePrivate(const QAndroidTimeZonePrivate &other);
     ~QAndroidTimeZonePrivate();
 
-    QTimeZonePrivate *clone() Q_DECL_OVERRIDE;
+    QAndroidTimeZonePrivate *clone() const override;
 
     QString displayName(QTimeZone::TimeType timeType, QTimeZone::NameType nameType,
                         const QLocale &locale) const Q_DECL_OVERRIDE;
diff --git a/src/corelib/tools/qtimezoneprivate_tz.cpp b/src/corelib/tools/qtimezoneprivate_tz.cpp
index 7cd5d6d506..1714c9802f 100644
--- a/src/corelib/tools/qtimezoneprivate_tz.cpp
+++ b/src/corelib/tools/qtimezoneprivate_tz.cpp
@@ -629,7 +629,7 @@ QTzTimeZonePrivate::~QTzTimeZonePrivate()
 {
 }
 
-QTimeZonePrivate *QTzTimeZonePrivate::clone()
+QTzTimeZonePrivate *QTzTimeZonePrivate::clone() const
 {
     return new QTzTimeZonePrivate(*this);
 }
diff --git a/src/corelib/tools/qtimezoneprivate_win.cpp b/src/corelib/tools/qtimezoneprivate_win.cpp
index 4febeda537..16dfaefb74 100644
--- a/src/corelib/tools/qtimezoneprivate_win.cpp
+++ b/src/corelib/tools/qtimezoneprivate_win.cpp
@@ -415,7 +415,7 @@ QWinTimeZonePrivate::~QWinTimeZonePrivate()
 {
 }
 
-QTimeZonePrivate *QWinTimeZonePrivate::clone()
+QWinTimeZonePrivate *QWinTimeZonePrivate::clone() const
 {
     return new QWinTimeZonePrivate(*this);
 }