diff --git a/src/fontcache.cpp b/src/fontcache.cpp
index 0449a79e01..54ebf6443c 100644
--- a/src/fontcache.cpp
+++ b/src/fontcache.cpp
@@ -72,7 +72,7 @@ public:
 	~SpriteFontCache();
 	virtual SpriteID GetUnicodeGlyph(WChar key);
 	virtual void SetUnicodeGlyph(WChar key, SpriteID sprite);
-	virtual void InitializeUnicodeGlyphMap();
+	virtual void InitializeUnicodeGlyphMap() override;
 	virtual void ClearFontCache();
 	virtual const Sprite *GetGlyph(GlyphID key);
 	virtual uint GetGlyphWidth(GlyphID key);
diff --git a/src/fontcache_internal.h b/src/fontcache_internal.h
index 701b70956d..ac4370f685 100644
--- a/src/fontcache_internal.h
+++ b/src/fontcache_internal.h
@@ -66,7 +66,7 @@ public:
 	SpriteID GetUnicodeGlyph(WChar key) override { return this->parent->GetUnicodeGlyph(key); }
 	void SetUnicodeGlyph(WChar key, SpriteID sprite) override { this->parent->SetUnicodeGlyph(key, sprite); }
 
-	virtual void InitializeUnicodeGlyphMap()
+	virtual void InitializeUnicodeGlyphMap() override
 	{
 		this->parent->InitializeUnicodeGlyphMap();
 		font_height_cache[this->fs] = this->GetHeight();
diff --git a/src/plans_gui.cpp b/src/plans_gui.cpp
index d793ffbd15..5f8f09be41 100644
--- a/src/plans_gui.cpp
+++ b/src/plans_gui.cpp
@@ -107,7 +107,7 @@ struct PlansWindow : Window {
 		}
 	}
 
-	virtual void OnClick(Point pt, int widget, int click_count)
+	virtual void OnClick(Point pt, int widget, int click_count) override
 	{
 		switch (widget) {
 			case WID_PLN_NEW:
@@ -232,7 +232,7 @@ struct PlansWindow : Window {
 		}
 	}
 
-	virtual void OnQueryTextFinished(char *str)
+	virtual void OnQueryTextFinished(char *str) override
 	{
 		if (_current_plan == nullptr || str == nullptr) return;
 
@@ -247,7 +247,7 @@ struct PlansWindow : Window {
 		return true;
 	}
 
-	virtual void OnPaint()
+	virtual void OnPaint() override
 	{
 		this->SetWidgetDisabledState(WID_PLN_HIDE_ALL, this->vscroll->GetCount() == 0);
 		this->SetWidgetDisabledState(WID_PLN_SHOW_ALL, this->vscroll->GetCount() == 0);
@@ -261,7 +261,7 @@ struct PlansWindow : Window {
 		this->DrawWidgets();
 	}
 
-	virtual void DrawWidget(const Rect &r, int widget) const
+	virtual void DrawWidget(const Rect &r, int widget) const override
 	{
 		switch (widget) {
 			case WID_PLN_LIST: {
@@ -323,12 +323,12 @@ struct PlansWindow : Window {
 		}
 	}
 
-	virtual void OnResize()
+	virtual void OnResize() override
 	{
 		this->vscroll->SetCapacityFromWidget(this, WID_PLN_LIST, WD_FRAMERECT_TOP + WD_FRAMERECT_BOTTOM);
 	}
 
-	virtual void UpdateWidgetSize(int widget, Dimension *size, const Dimension &padding, Dimension *fill, Dimension *resize)
+	virtual void UpdateWidgetSize(int widget, Dimension *size, const Dimension &padding, Dimension *fill, Dimension *resize) override
 	{
 		switch (widget) {
 			case WID_PLN_LIST:
@@ -369,14 +369,14 @@ struct PlansWindow : Window {
 	}
 
 	/** The drawing of a line starts. */
-	virtual void OnPlaceObject(Point pt, TileIndex tile)
+	virtual void OnPlaceObject(Point pt, TileIndex tile) override
 	{
 		/* A player can't add lines to a public plan of another company. */
 		if (_current_plan && _current_plan->owner == _local_company) VpStartPlaceSizing(tile, VPM_X_AND_Y, DDSP_DRAW_PLANLINE);
 	}
 
 	/** The drawing of a line is in progress. */
-	virtual void OnPlaceDrag(ViewportPlaceMethod select_method, ViewportDragDropSelectionProcess select_proc, Point pt)
+	virtual void OnPlaceDrag(ViewportPlaceMethod select_method, ViewportDragDropSelectionProcess select_proc, Point pt) override
 	{
 		const Point p = GetTileBelowCursor();
 		const TileIndex tile = TileVirtXY(p.x, p.y);
@@ -387,13 +387,13 @@ struct PlansWindow : Window {
 	}
 
 	/** The drawing of a line ends up normally. */
-	virtual void OnPlaceMouseUp(ViewportPlaceMethod select_method, ViewportDragDropSelectionProcess select_proc, Point pt, TileIndex start_tile, TileIndex end_tile)
+	virtual void OnPlaceMouseUp(ViewportPlaceMethod select_method, ViewportDragDropSelectionProcess select_proc, Point pt, TileIndex start_tile, TileIndex end_tile) override
 	{
 		if (_current_plan) _current_plan->ValidateNewLine();
 	}
 
 	/** The drawing of a line is aborted. */
-	virtual void OnPlaceObjectAbort()
+	virtual void OnPlaceObjectAbort() override
 	{
 		if (_current_plan) {
 			_current_plan->temp_line->MarkDirty();
diff --git a/src/table/newgrf_debug_data.h b/src/table/newgrf_debug_data.h
index 9d6d8fc662..3ea901f7f8 100644
--- a/src/table/newgrf_debug_data.h
+++ b/src/table/newgrf_debug_data.h
@@ -947,7 +947,7 @@ class NIHTown : public NIHelper {
 		return nullptr;
 	}
 
-	virtual std::vector<uint32> GetPSAGRFIDs(uint index) const
+	virtual std::vector<uint32> GetPSAGRFIDs(uint index) const override
 	{
 		Town *t = Town::Get(index);
 
diff --git a/src/tbtr_template_gui_create.cpp b/src/tbtr_template_gui_create.cpp
index 65c5fc538a..00d0b3c97f 100644
--- a/src/tbtr_template_gui_create.cpp
+++ b/src/tbtr_template_gui_create.cpp
@@ -191,7 +191,7 @@ public:
 		UpdateButtonState();
 	}
 
-	virtual void OnResize()
+	virtual void OnResize() override
 	{
 		NWidgetCore *template_panel = this->GetWidget<NWidgetCore>(TCW_NEW_TMPL_PANEL);
 		this->hscroll->SetCapacity(template_panel->current_x);
@@ -201,7 +201,7 @@ public:
 	}
 
 
-	virtual void OnInvalidateData(int data = 0, bool gui_scope = true)
+	virtual void OnInvalidateData(int data = 0, bool gui_scope = true) override
 	{
 		if(!gui_scope) return;
 
@@ -215,7 +215,7 @@ public:
 		UpdateButtonState();
 	}
 
-	virtual void OnClick(Point pt, int widget, int click_count)
+	virtual void OnClick(Point pt, int widget, int click_count) override
 	{
 		switch(widget) {
 			case TCW_NEW_TMPL_PANEL: {
@@ -259,7 +259,7 @@ public:
 		}
 	}
 
-	virtual bool OnVehicleSelect(const Vehicle *v)
+	virtual bool OnVehicleSelect(const Vehicle *v) override
 	{
 		// throw away the current virtual train
 		if (virtual_train != nullptr) {
@@ -276,7 +276,7 @@ public:
 		return true;
 	}
 
-	virtual void OnPlaceObjectAbort()
+	virtual void OnPlaceObjectAbort() override
 	{
 		this->sel = INVALID_VEHICLE;
 		this->vehicle_over = INVALID_VEHICLE;
@@ -284,7 +284,7 @@ public:
 		this->SetDirty();
 	}
 
-	virtual void DrawWidget(const Rect &r, int widget) const
+	virtual void DrawWidget(const Rect &r, int widget) const override
 	{
 		switch(widget) {
 			case TCW_NEW_TMPL_PANEL: {
@@ -364,7 +364,7 @@ public:
 		}
 	}
 
-	virtual void OnDragDrop(Point pt, int widget)
+	virtual void OnDragDrop(Point pt, int widget) override
 	{
 		switch (widget) {
 			case TCW_NEW_TMPL_PANEL: {
@@ -425,7 +425,7 @@ public:
 		this->SetDirty();
 	}
 
-	virtual void OnMouseDrag(Point pt, int widget)
+	virtual void OnMouseDrag(Point pt, int widget) override
 	{
 		if (this->sel == INVALID_VEHICLE) return;
 
@@ -470,7 +470,7 @@ public:
 		this->SetWidgetDirty(widget);
 	}
 
-	virtual void OnPaint()
+	virtual void OnPaint() override
 	{
 		uint min_width = 32;
 		uint min_height = 30;