diff --git a/src/qt/addressbookpage.h b/src/qt/addressbookpage.h
--- a/src/qt/addressbookpage.h
+++ b/src/qt/addressbookpage.h
@@ -43,7 +43,7 @@
     const QString &getReturnValue() const { return returnValue; }
 
 public Q_SLOTS:
-    void done(int retval);
+    void done(int retval) override;
 
 private:
     Ui::AddressBookPage *ui;
diff --git a/src/qt/addresstablemodel.h b/src/qt/addresstablemodel.h
--- a/src/qt/addresstablemodel.h
+++ b/src/qt/addresstablemodel.h
@@ -59,16 +59,18 @@
 
     /** @name Methods overridden from QAbstractTableModel
         @{*/
-    int rowCount(const QModelIndex &parent) const;
-    int columnCount(const QModelIndex &parent) const;
-    QVariant data(const QModelIndex &index, int role) const;
-    bool setData(const QModelIndex &index, const QVariant &value, int role);
+    int rowCount(const QModelIndex &parent) const override;
+    int columnCount(const QModelIndex &parent) const override;
+    QVariant data(const QModelIndex &index, int role) const override;
+    bool setData(const QModelIndex &index, const QVariant &value,
+                 int role) override;
     QVariant headerData(int section, Qt::Orientation orientation,
-                        int role) const;
-    QModelIndex index(int row, int column, const QModelIndex &parent) const;
+                        int role) const override;
+    QModelIndex index(int row, int column,
+                      const QModelIndex &parent) const override;
     bool removeRows(int row, int count,
-                    const QModelIndex &parent = QModelIndex());
-    Qt::ItemFlags flags(const QModelIndex &index) const;
+                    const QModelIndex &parent = QModelIndex()) override;
+    Qt::ItemFlags flags(const QModelIndex &index) const override;
     /*@}*/
 
     /* Add an address to the model.
diff --git a/src/qt/askpassphrasedialog.h b/src/qt/askpassphrasedialog.h
--- a/src/qt/askpassphrasedialog.h
+++ b/src/qt/askpassphrasedialog.h
@@ -30,7 +30,7 @@
     explicit AskPassphraseDialog(Mode mode, QWidget *parent);
     ~AskPassphraseDialog();
 
-    void accept();
+    void accept() override;
 
     void setModel(WalletModel *model);
 
@@ -45,8 +45,8 @@
     void secureClearPassFields();
 
 protected:
-    bool event(QEvent *event);
-    bool eventFilter(QObject *object, QEvent *event);
+    bool event(QEvent *event) override;
+    bool eventFilter(QObject *object, QEvent *event) override;
 };
 
 #endif // BITCOIN_QT_ASKPASSPHRASEDIALOG_H
diff --git a/src/qt/bantablemodel.h b/src/qt/bantablemodel.h
--- a/src/qt/bantablemodel.h
+++ b/src/qt/bantablemodel.h
@@ -46,14 +46,15 @@
 
     /** @name Methods overridden from QAbstractTableModel
         @{*/
-    int rowCount(const QModelIndex &parent) const;
-    int columnCount(const QModelIndex &parent) const;
-    QVariant data(const QModelIndex &index, int role) const;
+    int rowCount(const QModelIndex &parent) const override;
+    int columnCount(const QModelIndex &parent) const override;
+    QVariant data(const QModelIndex &index, int role) const override;
     QVariant headerData(int section, Qt::Orientation orientation,
-                        int role) const;
-    QModelIndex index(int row, int column, const QModelIndex &parent) const;
-    Qt::ItemFlags flags(const QModelIndex &index) const;
-    void sort(int column, Qt::SortOrder order);
+                        int role) const override;
+    QModelIndex index(int row, int column,
+                      const QModelIndex &parent) const override;
+    Qt::ItemFlags flags(const QModelIndex &index) const override;
+    void sort(int column, Qt::SortOrder order) override;
     bool shouldShow();
     /*@}*/
 
diff --git a/src/qt/bitcoinamountfield.h b/src/qt/bitcoinamountfield.h
--- a/src/qt/bitcoinamountfield.h
+++ b/src/qt/bitcoinamountfield.h
@@ -61,7 +61,7 @@
 
 protected:
     /** Intercept focus-in event and ',' key presses */
-    bool eventFilter(QObject *object, QEvent *event);
+    bool eventFilter(QObject *object, QEvent *event) override;
 
 private:
     AmountSpinBox *amount;
diff --git a/src/qt/bitcoingui.h b/src/qt/bitcoingui.h
--- a/src/qt/bitcoingui.h
+++ b/src/qt/bitcoingui.h
@@ -76,12 +76,12 @@
     bool enableWallet;
 
 protected:
-    void changeEvent(QEvent *e);
-    void closeEvent(QCloseEvent *event);
-    void showEvent(QShowEvent *event);
-    void dragEnterEvent(QDragEnterEvent *event);
-    void dropEvent(QDropEvent *event);
-    bool eventFilter(QObject *object, QEvent *event);
+    void changeEvent(QEvent *e) override;
+    void closeEvent(QCloseEvent *event) override;
+    void showEvent(QShowEvent *event) override;
+    void dragEnterEvent(QDragEnterEvent *event) override;
+    void dropEvent(QDropEvent *event) override;
+    bool eventFilter(QObject *object, QEvent *event) override;
 
 private:
     ClientModel *clientModel;
@@ -270,7 +270,7 @@
 
 protected:
     /** So that it responds to left-button clicks */
-    void mousePressEvent(QMouseEvent *event);
+    void mousePressEvent(QMouseEvent *event) override;
 
 private:
     OptionsModel *optionsModel;
diff --git a/src/qt/coincontroldialog.h b/src/qt/coincontroldialog.h
--- a/src/qt/coincontroldialog.h
+++ b/src/qt/coincontroldialog.h
@@ -36,7 +36,7 @@
     CCoinControlWidgetItem(QTreeWidgetItem *parent, int type = Type)
         : QTreeWidgetItem(parent, type) {}
 
-    bool operator<(const QTreeWidgetItem &other) const;
+    bool operator<(const QTreeWidgetItem &other) const override;
 };
 
 class CoinControlDialog : public QDialog {
diff --git a/src/qt/coincontroltreewidget.h b/src/qt/coincontroltreewidget.h
--- a/src/qt/coincontroltreewidget.h
+++ b/src/qt/coincontroltreewidget.h
@@ -15,7 +15,7 @@
     explicit CoinControlTreeWidget(QWidget *parent = 0);
 
 protected:
-    virtual void keyPressEvent(QKeyEvent *event);
+    virtual void keyPressEvent(QKeyEvent *event) override;
 };
 
 #endif // BITCOIN_QT_COINCONTROLTREEWIDGET_H
diff --git a/src/qt/editaddressdialog.h b/src/qt/editaddressdialog.h
--- a/src/qt/editaddressdialog.h
+++ b/src/qt/editaddressdialog.h
@@ -40,7 +40,7 @@
     void setAddress(const QString &address);
 
 public Q_SLOTS:
-    void accept();
+    void accept() override;
 
 private:
     bool saveCurrentRow();
diff --git a/src/qt/guiutil.h b/src/qt/guiutil.h
--- a/src/qt/guiutil.h
+++ b/src/qt/guiutil.h
@@ -152,7 +152,7 @@
     explicit ToolTipToRichTextFilter(int size_threshold, QObject *parent = 0);
 
 protected:
-    bool eventFilter(QObject *obj, QEvent *evt);
+    bool eventFilter(QObject *obj, QEvent *evt) override;
 
 private:
     int size_threshold;
@@ -240,7 +240,7 @@
     void clicked(const QPoint &point);
 
 protected:
-    void mouseReleaseEvent(QMouseEvent *event);
+    void mouseReleaseEvent(QMouseEvent *event) override;
 };
 
 class ClickableProgressBar : public QProgressBar {
@@ -253,7 +253,7 @@
     void clicked(const QPoint &point);
 
 protected:
-    void mouseReleaseEvent(QMouseEvent *event);
+    void mouseReleaseEvent(QMouseEvent *event) override;
 };
 
 #if defined(Q_OS_MAC) && QT_VERSION >= 0x050000
@@ -261,7 +261,7 @@
 // https://bugreports.qt-project.org/browse/QTBUG-15631
 // QProgressBar uses around 10% CPU even when app is in background
 class ProgressBar : public ClickableProgressBar {
-    bool event(QEvent *e) {
+    bool event(QEvent *e) override {
         return (e->type() != QEvent::StyleAnimationUpdate)
                    ? QProgressBar::event(e)
                    : false;
diff --git a/src/qt/modaloverlay.h b/src/qt/modaloverlay.h
--- a/src/qt/modaloverlay.h
+++ b/src/qt/modaloverlay.h
@@ -36,8 +36,8 @@
     bool isLayerVisible() { return layerIsVisible; }
 
 protected:
-    bool eventFilter(QObject *obj, QEvent *ev);
-    bool event(QEvent *ev);
+    bool eventFilter(QObject *obj, QEvent *ev) override;
+    bool event(QEvent *ev) override;
 
 private:
     Ui::ModalOverlay *ui;
diff --git a/src/qt/openuridialog.h b/src/qt/openuridialog.h
--- a/src/qt/openuridialog.h
+++ b/src/qt/openuridialog.h
@@ -23,7 +23,7 @@
     QString getURI();
 
 protected Q_SLOTS:
-    void accept();
+    void accept() override;
 
 private Q_SLOTS:
     void on_selectFileButton_clicked();
diff --git a/src/qt/optionsdialog.h b/src/qt/optionsdialog.h
--- a/src/qt/optionsdialog.h
+++ b/src/qt/optionsdialog.h
@@ -26,7 +26,7 @@
 public:
     explicit ProxyAddressValidator(QObject *parent);
 
-    State validate(QString &input, int &pos) const;
+    State validate(QString &input, int &pos) const override;
 };
 
 /** Preferences dialog. */
diff --git a/src/qt/optionsmodel.h b/src/qt/optionsmodel.h
--- a/src/qt/optionsmodel.h
+++ b/src/qt/optionsmodel.h
@@ -51,10 +51,11 @@
     void Init(bool resetSettings = false);
     void Reset();
 
-    int rowCount(const QModelIndex &parent = QModelIndex()) const;
-    QVariant data(const QModelIndex &index, int role = Qt::DisplayRole) const;
+    int rowCount(const QModelIndex &parent = QModelIndex()) const override;
+    QVariant data(const QModelIndex &index,
+                  int role = Qt::DisplayRole) const override;
     bool setData(const QModelIndex &index, const QVariant &value,
-                 int role = Qt::EditRole);
+                 int role = Qt::EditRole) override;
     /** Updates current unit in memory, settings and emits
      * displayUnitChanged(newUnit) signal */
     void setDisplayUnit(const QVariant &value);
diff --git a/src/qt/paymentserver.h b/src/qt/paymentserver.h
--- a/src/qt/paymentserver.h
+++ b/src/qt/paymentserver.h
@@ -123,7 +123,7 @@
 protected:
     // Constructor registers this on the parent QApplication to receive
     // QEvent::FileOpen and QEvent:Drop events
-    bool eventFilter(QObject *object, QEvent *event);
+    bool eventFilter(QObject *object, QEvent *event) override;
 
 private:
     static bool readPaymentRequestFromFile(const QString &filename,
diff --git a/src/qt/peertablemodel.h b/src/qt/peertablemodel.h
--- a/src/qt/peertablemodel.h
+++ b/src/qt/peertablemodel.h
@@ -55,14 +55,15 @@
 
     /** @name Methods overridden from QAbstractTableModel
         @{*/
-    int rowCount(const QModelIndex &parent) const;
-    int columnCount(const QModelIndex &parent) const;
-    QVariant data(const QModelIndex &index, int role) const;
+    int rowCount(const QModelIndex &parent) const override;
+    int columnCount(const QModelIndex &parent) const override;
+    QVariant data(const QModelIndex &index, int role) const override;
     QVariant headerData(int section, Qt::Orientation orientation,
-                        int role) const;
-    QModelIndex index(int row, int column, const QModelIndex &parent) const;
-    Qt::ItemFlags flags(const QModelIndex &index) const;
-    void sort(int column, Qt::SortOrder order);
+                        int role) const override;
+    QModelIndex index(int row, int column,
+                      const QModelIndex &parent) const override;
+    Qt::ItemFlags flags(const QModelIndex &index) const override;
+    void sort(int column, Qt::SortOrder order) override;
     /*@}*/
 
 public Q_SLOTS:
diff --git a/src/qt/qvalidatedlineedit.h b/src/qt/qvalidatedlineedit.h
--- a/src/qt/qvalidatedlineedit.h
+++ b/src/qt/qvalidatedlineedit.h
@@ -21,8 +21,8 @@
     bool isValid();
 
 protected:
-    void focusInEvent(QFocusEvent *evt);
-    void focusOutEvent(QFocusEvent *evt);
+    void focusInEvent(QFocusEvent *evt) override;
+    void focusOutEvent(QFocusEvent *evt) override;
 
 private:
     bool valid;
diff --git a/src/qt/receiverequestdialog.h b/src/qt/receiverequestdialog.h
--- a/src/qt/receiverequestdialog.h
+++ b/src/qt/receiverequestdialog.h
@@ -39,8 +39,8 @@
     void copyImage();
 
 protected:
-    virtual void mousePressEvent(QMouseEvent *event);
-    virtual void contextMenuEvent(QContextMenuEvent *event);
+    virtual void mousePressEvent(QMouseEvent *event) override;
+    virtual void contextMenuEvent(QContextMenuEvent *event) override;
 
 private:
     QMenu *contextMenu;
diff --git a/src/qt/recentrequeststablemodel.h b/src/qt/recentrequeststablemodel.h
--- a/src/qt/recentrequeststablemodel.h
+++ b/src/qt/recentrequeststablemodel.h
@@ -71,16 +71,18 @@
 
     /** @name Methods overridden from QAbstractTableModel
         @{*/
-    int rowCount(const QModelIndex &parent) const;
-    int columnCount(const QModelIndex &parent) const;
-    QVariant data(const QModelIndex &index, int role) const;
-    bool setData(const QModelIndex &index, const QVariant &value, int role);
+    int rowCount(const QModelIndex &parent) const override;
+    int columnCount(const QModelIndex &parent) const override;
+    QVariant data(const QModelIndex &index, int role) const override;
+    bool setData(const QModelIndex &index, const QVariant &value,
+                 int role) override;
     QVariant headerData(int section, Qt::Orientation orientation,
-                        int role) const;
-    QModelIndex index(int row, int column, const QModelIndex &parent) const;
+                        int role) const override;
+    QModelIndex index(int row, int column,
+                      const QModelIndex &parent) const override;
     bool removeRows(int row, int count,
-                    const QModelIndex &parent = QModelIndex());
-    Qt::ItemFlags flags(const QModelIndex &index) const;
+                    const QModelIndex &parent = QModelIndex()) override;
+    Qt::ItemFlags flags(const QModelIndex &index) const override;
     /*@}*/
 
     const RecentRequestEntry &entry(int row) const { return list[row]; }
@@ -89,7 +91,7 @@
     void addNewRequest(RecentRequestEntry &recipient);
 
 public Q_SLOTS:
-    void sort(int column, Qt::SortOrder order = Qt::AscendingOrder);
+    void sort(int column, Qt::SortOrder order = Qt::AscendingOrder) override;
     void updateDisplayUnit();
 
 private:
diff --git a/src/qt/rpcconsole.h b/src/qt/rpcconsole.h
--- a/src/qt/rpcconsole.h
+++ b/src/qt/rpcconsole.h
@@ -58,8 +58,8 @@
     };
 
 protected:
-    virtual bool eventFilter(QObject *obj, QEvent *event);
-    void keyPressEvent(QKeyEvent *);
+    virtual bool eventFilter(QObject *obj, QEvent *event) override;
+    void keyPressEvent(QKeyEvent *) override;
 
 private Q_SLOTS:
     void on_lineEdit_returnPressed();
@@ -70,9 +70,9 @@
     void on_sldGraphRange_valueChanged(int value);
     /** update traffic statistics */
     void updateTrafficStats(quint64 totalBytesIn, quint64 totalBytesOut);
-    void resizeEvent(QResizeEvent *event);
-    void showEvent(QShowEvent *event);
-    void hideEvent(QHideEvent *event);
+    void resizeEvent(QResizeEvent *event) override;
+    void showEvent(QShowEvent *event) override;
+    void hideEvent(QHideEvent *event) override;
     /** Show custom context menu on Peers tab */
     void showPeersTableContextMenu(const QPoint &point);
     /** Show custom context menu on Bans tab */
diff --git a/src/qt/rpcconsole.cpp b/src/qt/rpcconsole.cpp
--- a/src/qt/rpcconsole.cpp
+++ b/src/qt/rpcconsole.cpp
@@ -110,8 +110,9 @@
 class QtRPCTimerInterface : public RPCTimerInterface {
 public:
     ~QtRPCTimerInterface() {}
-    const char *Name() { return "Qt"; }
-    RPCTimerBase *NewTimer(std::function<void(void)> &func, int64_t millis) {
+    const char *Name() override { return "Qt"; }
+    RPCTimerBase *NewTimer(std::function<void(void)> &func,
+                           int64_t millis) override {
         return new QtRPCTimerBase(func, millis);
     }
 };
diff --git a/src/qt/sendcoinsdialog.h b/src/qt/sendcoinsdialog.h
--- a/src/qt/sendcoinsdialog.h
+++ b/src/qt/sendcoinsdialog.h
@@ -51,8 +51,8 @@
 
 public Q_SLOTS:
     void clear();
-    void reject();
-    void accept();
+    void reject() override;
+    void accept() override;
     SendCoinsEntry *addEntry();
     void updateTabsAndLabels();
     void setBalance(const CAmount &balance, const CAmount &unconfirmedBalance,
diff --git a/src/qt/signverifymessagedialog.h b/src/qt/signverifymessagedialog.h
--- a/src/qt/signverifymessagedialog.h
+++ b/src/qt/signverifymessagedialog.h
@@ -30,7 +30,7 @@
     void showTab_VM(bool fShow);
 
 protected:
-    bool eventFilter(QObject *object, QEvent *event);
+    bool eventFilter(QObject *object, QEvent *event) override;
 
 private:
     Ui::SignVerifyMessageDialog *ui;
diff --git a/src/qt/splashscreen.h b/src/qt/splashscreen.h
--- a/src/qt/splashscreen.h
+++ b/src/qt/splashscreen.h
@@ -24,8 +24,8 @@
     ~SplashScreen();
 
 protected:
-    void paintEvent(QPaintEvent *event);
-    void closeEvent(QCloseEvent *event);
+    void paintEvent(QPaintEvent *event) override;
+    void closeEvent(QCloseEvent *event) override;
 
 public Q_SLOTS:
     /** Slot to call finish() method as it's not defined as slot */
diff --git a/src/qt/trafficgraphwidget.h b/src/qt/trafficgraphwidget.h
--- a/src/qt/trafficgraphwidget.h
+++ b/src/qt/trafficgraphwidget.h
@@ -24,7 +24,7 @@
     int getGraphRangeMins() const;
 
 protected:
-    void paintEvent(QPaintEvent *);
+    void paintEvent(QPaintEvent *) override;
 
 public Q_SLOTS:
     void updateRates();
diff --git a/src/qt/transactionfilterproxy.h b/src/qt/transactionfilterproxy.h
--- a/src/qt/transactionfilterproxy.h
+++ b/src/qt/transactionfilterproxy.h
@@ -47,11 +47,11 @@
     /** Set whether to show conflicted transactions. */
     void setShowInactive(bool showInactive);
 
-    int rowCount(const QModelIndex &parent = QModelIndex()) const;
+    int rowCount(const QModelIndex &parent = QModelIndex()) const override;
 
 protected:
     bool filterAcceptsRow(int source_row,
-                          const QModelIndex &source_parent) const;
+                          const QModelIndex &source_parent) const override;
 
 private:
     QDateTime dateFrom;
diff --git a/src/qt/transactiontablemodel.h b/src/qt/transactiontablemodel.h
--- a/src/qt/transactiontablemodel.h
+++ b/src/qt/transactiontablemodel.h
@@ -75,13 +75,13 @@
         RawDecorationRole,
     };
 
-    int rowCount(const QModelIndex &parent) const;
-    int columnCount(const QModelIndex &parent) const;
-    QVariant data(const QModelIndex &index, int role) const;
+    int rowCount(const QModelIndex &parent) const override;
+    int columnCount(const QModelIndex &parent) const override;
+    QVariant data(const QModelIndex &index, int role) const override;
     QVariant headerData(int section, Qt::Orientation orientation,
-                        int role) const;
+                        int role) const override;
     QModelIndex index(int row, int column,
-                      const QModelIndex &parent = QModelIndex()) const;
+                      const QModelIndex &parent = QModelIndex()) const override;
     bool processingQueuedTransactions() {
         return fProcessingQueuedTransactions;
     }
diff --git a/src/qt/transactionview.h b/src/qt/transactionview.h
--- a/src/qt/transactionview.h
+++ b/src/qt/transactionview.h
@@ -81,9 +81,9 @@
 
     GUIUtil::TableViewLastColumnResizingFixer *columnResizingFixer;
 
-    virtual void resizeEvent(QResizeEvent *event);
+    virtual void resizeEvent(QResizeEvent *event) override;
 
-    bool eventFilter(QObject *obj, QEvent *event);
+    bool eventFilter(QObject *obj, QEvent *event) override;
 
 private Q_SLOTS:
     void contextualMenu(const QPoint &);
diff --git a/src/qt/utilitydialog.h b/src/qt/utilitydialog.h
--- a/src/qt/utilitydialog.h
+++ b/src/qt/utilitydialog.h
@@ -43,7 +43,7 @@
     static QWidget *showShutdownWindow(BitcoinGUI *window);
 
 protected:
-    void closeEvent(QCloseEvent *event);
+    void closeEvent(QCloseEvent *event) override;
 };
 
 #endif // BITCOIN_QT_UTILITYDIALOG_H