diff --git a/LibGUI/GButton.cpp b/LibGUI/GButton.cpp
index 59729e2e0d..3eea022f3a 100644
--- a/LibGUI/GButton.cpp
+++ b/LibGUI/GButton.cpp
@@ -4,7 +4,7 @@
 GButton::GButton(GWidget* parent)
     : GWidget(parent)
 {
-    setFillWithBackgroundColor(false);
+    set_fill_with_background_color(false);
 }
 
 GButton::~GButton()
@@ -19,11 +19,11 @@ void GButton::set_caption(String&& caption)
     update();
 }
 
-void GButton::paintEvent(GPaintEvent&)
+void GButton::paint_event(GPaintEvent&)
 {
-    Color buttonColor = Color::LightGray;
-    Color highlightColor = Color::White;
-    Color shadowColor = Color(96, 96, 96);
+    Color button_color = Color::LightGray;
+    Color highlight_color = Color::White;
+    Color shadow_color = Color(96, 96, 96);
 
     Painter painter(*this);
 
@@ -34,26 +34,26 @@ void GButton::paintEvent(GPaintEvent&)
 
     if (m_being_pressed) {
         // Base
-        painter.fill_rect({ 1, 1, width() - 2, height() - 2 }, buttonColor);
+        painter.fill_rect({ 1, 1, width() - 2, height() - 2 }, button_color);
 
         // Sunken shadow
-        painter.draw_line({ 1, 1 }, { width() - 2, 1 }, shadowColor);
-        painter.draw_line({ 1, 2 }, {1, height() - 2 }, shadowColor);
+        painter.draw_line({ 1, 1 }, { width() - 2, 1 }, shadow_color);
+        painter.draw_line({ 1, 2 }, {1, height() - 2 }, shadow_color);
     } else {
         // Base
-        painter.fill_rect({ 3, 3, width() - 5, height() - 5 }, buttonColor);
+        painter.fill_rect({ 3, 3, width() - 5, height() - 5 }, button_color);
 
         // White highlight
-        painter.draw_line({ 1, 1 }, { width() - 2, 1 }, highlightColor);
-        painter.draw_line({ 1, 2 }, { width() - 3, 2 }, highlightColor);
-        painter.draw_line({ 1, 3 }, { 1, height() - 2 }, highlightColor);
-        painter.draw_line({ 2, 3 }, { 2, height() - 3 }, highlightColor);
+        painter.draw_line({ 1, 1 }, { width() - 2, 1 }, highlight_color);
+        painter.draw_line({ 1, 2 }, { width() - 3, 2 }, highlight_color);
+        painter.draw_line({ 1, 3 }, { 1, height() - 2 }, highlight_color);
+        painter.draw_line({ 2, 3 }, { 2, height() - 3 }, highlight_color);
 
         // Gray shadow 
-        painter.draw_line({ width() - 2, 1 }, { width() - 2, height() - 4 }, shadowColor);
-        painter.draw_line({ width() - 3, 2 }, { width() - 3, height() - 4 }, shadowColor);
-        painter.draw_line({ 1, height() - 2 }, { width() - 2, height() - 2 }, shadowColor);
-        painter.draw_line({ 2, height() - 3 }, { width() - 2, height() - 3 }, shadowColor);
+        painter.draw_line({ width() - 2, 1 }, { width() - 2, height() - 4 }, shadow_color);
+        painter.draw_line({ width() - 3, 2 }, { width() - 3, height() - 4 }, shadow_color);
+        painter.draw_line({ 1, height() - 2 }, { width() - 2, height() - 2 }, shadow_color);
+        painter.draw_line({ 2, height() - 3 }, { width() - 2, height() - 3 }, shadow_color);
     }
 
     if (!caption().is_empty()) {
@@ -64,24 +64,24 @@ void GButton::paintEvent(GPaintEvent&)
     }
 }
 
-void GButton::mouseDownEvent(GMouseEvent& event)
+void GButton::mousedown_event(GMouseEvent& event)
 {
     dbgprintf("Button::mouseDownEvent: x=%d, y=%d, button=%u\n", event.x(), event.y(), (unsigned)event.button());
 
     m_being_pressed = true;
 
     update();
-    GWidget::mouseDownEvent(event);
+    GWidget::mousedown_event(event);
 }
 
-void GButton::mouseUpEvent(GMouseEvent& event)
+void GButton::mouseup_event(GMouseEvent& event)
 {
     dbgprintf("Button::mouseUpEvent: x=%d, y=%d, button=%u\n", event.x(), event.y(), (unsigned)event.button());
 
     m_being_pressed = false;
 
     update();
-    GWidget::mouseUpEvent(event);
+    GWidget::mouseup_event(event);
 
     if (on_click)
         on_click(*this);
diff --git a/LibGUI/GButton.h b/LibGUI/GButton.h
index 78c73c23de..606311aac0 100644
--- a/LibGUI/GButton.h
+++ b/LibGUI/GButton.h
@@ -15,9 +15,9 @@ public:
     Function<void(GButton&)> on_click;
 
 private:
-    virtual void paintEvent(GPaintEvent&) override;
-    virtual void mouseDownEvent(GMouseEvent&) override;
-    virtual void mouseUpEvent(GMouseEvent&) override;
+    virtual void paint_event(GPaintEvent&) override;
+    virtual void mousedown_event(GMouseEvent&) override;
+    virtual void mouseup_event(GMouseEvent&) override;
 
     virtual const char* class_name() const override { return "GButton"; }
 
diff --git a/LibGUI/GCheckBox.cpp b/LibGUI/GCheckBox.cpp
index e2834cb29e..31d8361df1 100644
--- a/LibGUI/GCheckBox.cpp
+++ b/LibGUI/GCheckBox.cpp
@@ -11,7 +11,7 @@ GCheckBox::~GCheckBox()
 {
 }
 
-void GCheckBox::setCaption(String&& caption)
+void GCheckBox::set_caption(String&& caption)
 {
     if (caption == m_caption)
         return;
@@ -19,11 +19,11 @@ void GCheckBox::setCaption(String&& caption)
     update();
 }
 
-void GCheckBox::setIsChecked(bool b)
+void GCheckBox::set_checked(bool b)
 {
-    if (m_isChecked == b)
+    if (m_checked == b)
         return;
-    m_isChecked = b;
+    m_checked = b;
     update();
 }
 
@@ -72,10 +72,10 @@ static const char* checkedBitmap = {
     "###########"
 };
 
-void GCheckBox::paintEvent(GPaintEvent&)
+void GCheckBox::paint_event(GPaintEvent&)
 {
     Painter painter(*this);
-    auto bitmap = CharacterBitmap::create_from_ascii(isChecked() ? checkedBitmap : uncheckedBitmap, 11, 11);
+    auto bitmap = CharacterBitmap::create_from_ascii(is_checked() ? checkedBitmap : uncheckedBitmap, 11, 11);
 
     auto textRect = rect();
     textRect.set_left(bitmap->width() + 4);
@@ -85,18 +85,18 @@ void GCheckBox::paintEvent(GPaintEvent&)
     bitmapPosition.set_x(2);
     bitmapPosition.set_y(height() / 2 - bitmap->height() / 2 - 1);
 
-    painter.fill_rect(rect(), backgroundColor());
-    painter.draw_bitmap(bitmapPosition, *bitmap, foregroundColor());
+    painter.fill_rect(rect(), background_color());
+    painter.draw_bitmap(bitmapPosition, *bitmap, foreground_color());
 
     if (!caption().is_empty()) {
-        painter.draw_text(textRect, caption(), Painter::TextAlignment::TopLeft, foregroundColor());
+        painter.draw_text(textRect, caption(), Painter::TextAlignment::TopLeft, foreground_color());
     }
 }
 
-void GCheckBox::mouseDownEvent(GMouseEvent& event)
+void GCheckBox::mousedown_event(GMouseEvent& event)
 {
     dbgprintf("GCheckBox::mouseDownEvent: x=%d, y=%d, button=%u\n", event.x(), event.y(), (unsigned)event.button());
 
-    setIsChecked(!isChecked());
+    set_checked(!is_checked());
 }
 
diff --git a/LibGUI/GCheckBox.h b/LibGUI/GCheckBox.h
index 1d0c071443..3c5e2f3001 100644
--- a/LibGUI/GCheckBox.h
+++ b/LibGUI/GCheckBox.h
@@ -9,18 +9,18 @@ public:
     virtual ~GCheckBox() override;
 
     String caption() const { return m_caption; }
-    void setCaption(String&&);
+    void set_caption(String&&);
 
-    bool isChecked() const { return m_isChecked; }
-    void setIsChecked(bool);
+    bool is_checked() const { return m_checked; }
+    void set_checked(bool);
 
 private:
-    virtual void paintEvent(GPaintEvent&) override;
-    virtual void mouseDownEvent(GMouseEvent&) override;
+    virtual void paint_event(GPaintEvent&) override;
+    virtual void mousedown_event(GMouseEvent&) override;
 
     virtual const char* class_name() const override { return "GCheckBox"; }
 
     String m_caption;
-    bool m_isChecked { false };
+    bool m_checked { false };
 };
 
diff --git a/LibGUI/GLabel.cpp b/LibGUI/GLabel.cpp
index 472bc47ad2..8898dab096 100644
--- a/LibGUI/GLabel.cpp
+++ b/LibGUI/GLabel.cpp
@@ -10,7 +10,7 @@ GLabel::~GLabel()
 {
 }
 
-void GLabel::setText(String&& text)
+void GLabel::set_text(String&& text)
 {
     if (text == m_text)
         return;
@@ -18,11 +18,11 @@ void GLabel::setText(String&& text)
     update();
 }
 
-void GLabel::paintEvent(GPaintEvent&)
+void GLabel::paint_event(GPaintEvent&)
 {
     Painter painter(*this);
-    if (fillWithBackgroundColor())
-        painter.fill_rect({ 0, 0, width(), height() }, backgroundColor());
+    if (fill_with_background_color())
+        painter.fill_rect({ 0, 0, width(), height() }, background_color());
     if (!text().is_empty())
-        painter.draw_text({ 4, 4, width(), height() }, text(), Painter::TextAlignment::TopLeft, foregroundColor());
+        painter.draw_text({ 4, 4, width(), height() }, text(), Painter::TextAlignment::TopLeft, foreground_color());
 }
diff --git a/LibGUI/GLabel.h b/LibGUI/GLabel.h
index 9044faf84f..4e1446ffee 100644
--- a/LibGUI/GLabel.h
+++ b/LibGUI/GLabel.h
@@ -9,10 +9,10 @@ public:
     virtual ~GLabel() override;
 
     String text() const { return m_text; }
-    void setText(String&&);
+    void set_text(String&&);
 
 private:
-    virtual void paintEvent(GPaintEvent&) override;
+    virtual void paint_event(GPaintEvent&) override;
 
     virtual const char* class_name() const override { return "GLabel"; }
 
diff --git a/LibGUI/GListBox.cpp b/LibGUI/GListBox.cpp
index bc7027f8cf..f5a357792a 100644
--- a/LibGUI/GListBox.cpp
+++ b/LibGUI/GListBox.cpp
@@ -17,7 +17,7 @@ Rect GListBox::item_rect(int index) const
     return Rect { 2, 2 + (index * item_height), width() - 4, item_height };
 }
 
-void GListBox::paintEvent(GPaintEvent&)
+void GListBox::paint_event(GPaintEvent&)
 {
     Painter painter(*this);
 
@@ -25,32 +25,32 @@ void GListBox::paintEvent(GPaintEvent&)
     painter.fill_rect(rect(), Color::White);
     painter.draw_rect(rect(), Color::Black);
 
-    if (isFocused())
+    if (is_focused())
         painter.draw_focus_rect(rect());
 
-    for (int i = m_scrollOffset; i < static_cast<int>(m_items.size()); ++i) {
-        auto itemRect = item_rect(i);
-        Rect textRect(itemRect.x() + 1, itemRect.y() + 1, itemRect.width() - 2, itemRect.height() - 2);
+    for (int i = m_scroll_offset; i < static_cast<int>(m_items.size()); ++i) {
+        auto item_rect = this->item_rect(i);
+        Rect text_rect(item_rect.x() + 1, item_rect.y() + 1, item_rect.width() - 2, item_rect.height() - 2);
 
-        Color itemTextColor = foregroundColor();
-        if (m_selectedIndex == i) {
-            if (isFocused())
-                painter.fill_rect(itemRect, Color(0, 32, 128));
+        Color item_text_color = foreground_color();
+        if (m_selected_index == i) {
+            if (is_focused())
+                painter.fill_rect(item_rect, Color(0, 32, 128));
             else
-                painter.fill_rect(itemRect, Color(96, 96, 96));
-            itemTextColor = Color::White;
+                painter.fill_rect(item_rect, Color(96, 96, 96));
+            item_text_color = Color::White;
         }
-        painter.draw_text(textRect, m_items[i], Painter::TextAlignment::TopLeft, itemTextColor);
+        painter.draw_text(item_rect, m_items[i], Painter::TextAlignment::TopLeft, item_text_color);
     }
 }
 
-void GListBox::mouseDownEvent(GMouseEvent& event)
+void GListBox::mousedown_event(GMouseEvent& event)
 {
     dbgprintf("GListBox::mouseDownEvent %d,%d\n", event.x(), event.y());
-    for (int i = m_scrollOffset; i < static_cast<int>(m_items.size()); ++i) {
-        auto itemRect = item_rect(i);
-        if (itemRect.contains(event.position())) {
-            m_selectedIndex = i;
+    for (int i = m_scroll_offset; i < static_cast<int>(m_items.size()); ++i) {
+        auto item_rect = this->item_rect(i);
+        if (item_rect.contains(event.position())) {
+            m_selected_index = i;
             dbgprintf("GListBox: selected item %u (\"%s\")\n", i, m_items[i].characters());
             update();
             return;
@@ -58,10 +58,10 @@ void GListBox::mouseDownEvent(GMouseEvent& event)
     }
 }
 
-void GListBox::addItem(String&& item)
+void GListBox::add_item(String&& item)
 {
     m_items.append(move(item));
-    if (m_selectedIndex == -1)
-        m_selectedIndex = 0;
+    if (m_selected_index == -1)
+        m_selected_index = 0;
 }
 
diff --git a/LibGUI/GListBox.h b/LibGUI/GListBox.h
index 12750b7ddd..6668b424a0 100644
--- a/LibGUI/GListBox.h
+++ b/LibGUI/GListBox.h
@@ -7,18 +7,18 @@ public:
     explicit GListBox(GWidget* parent);
     virtual ~GListBox() override;
 
-    void addItem(String&&);
-    int selectedIndex() const { return m_selectedIndex; }
+    void add_item(String&&);
+    int selected_index() const { return m_selected_index; }
 
 private:
-    virtual void paintEvent(GPaintEvent&) override;
-    virtual void mouseDownEvent(GMouseEvent&) override;
+    virtual void paint_event(GPaintEvent&) override;
+    virtual void mousedown_event(GMouseEvent&) override;
     virtual const char* class_name() const override { return "GListBox"; }
 
     Rect item_rect(int index) const;
 
-    int m_scrollOffset { 0 };
-    int m_selectedIndex { -1 };
+    int m_scroll_offset { 0 };
+    int m_selected_index { -1 };
 
     Vector<String> m_items;
 };
diff --git a/LibGUI/GTextBox.cpp b/LibGUI/GTextBox.cpp
index 7319bab0af..cad25e171a 100644
--- a/LibGUI/GTextBox.cpp
+++ b/LibGUI/GTextBox.cpp
@@ -14,22 +14,22 @@ GTextBox::~GTextBox()
 {
 }
 
-void GTextBox::setText(String&& text)
+void GTextBox::set_text(String&& text)
 {
     m_text = move(text);
     m_cursorPosition = m_text.length();
     update();
 }
 
-void GTextBox::paintEvent(GPaintEvent&)
+void GTextBox::paint_event(GPaintEvent&)
 {
     Painter painter(*this);
 
     // FIXME: Reduce overdraw.
-    painter.fill_rect(rect(), backgroundColor());
-    painter.draw_rect(rect(), foregroundColor());
+    painter.fill_rect(rect(), background_color());
+    painter.draw_rect(rect(), foreground_color());
 
-    if (isFocused())
+    if (is_focused())
         painter.draw_focus_rect(rect());
 
     Rect innerRect = rect();
@@ -54,18 +54,18 @@ void GTextBox::paintEvent(GPaintEvent&)
         painter.draw_bitmap({x, y}, *bitmap, Color::Black);
     }
 
-    if (isFocused() && m_cursorBlinkState) {
+    if (is_focused() && m_cursorBlinkState) {
         unsigned visibleCursorPosition = m_cursorPosition - firstVisibleChar;
         Rect cursorRect(innerRect.x() + visibleCursorPosition * font().glyph_width(), innerRect.y(), 1, innerRect.height());
-        painter.fill_rect(cursorRect, foregroundColor());
+        painter.fill_rect(cursorRect, foreground_color());
     }
 }
 
-void GTextBox::mouseDownEvent(GMouseEvent&)
+void GTextBox::mousedown_event(GMouseEvent&)
 {
 }
 
-void GTextBox::handleBackspace()
+void GTextBox::handle_backspace()
 {
     if (m_cursorPosition == 0)
         return;
@@ -88,7 +88,7 @@ void GTextBox::handleBackspace()
     update();
 }
 
-void GTextBox::keyDownEvent(GKeyEvent& event)
+void GTextBox::keydown_event(GKeyEvent& event)
 {
     switch (event.key()) {
     case GKeyboardKey::LeftArrow:
@@ -104,7 +104,7 @@ void GTextBox::keyDownEvent(GKeyEvent& event)
         update();
         return;
     case GKeyboardKey::Backspace:
-        return handleBackspace();
+        return handle_backspace();
     case GKeyboardKey::Return:
         if (onReturnPressed)
             onReturnPressed(*this);
@@ -131,7 +131,7 @@ void GTextBox::keyDownEvent(GKeyEvent& event)
 void GTextBox::timerEvent(GTimerEvent&)
 {
     // FIXME: Disable the timer when not focused.
-    if (!isFocused())
+    if (!is_focused())
         return;
 
     m_cursorBlinkState = !m_cursorBlinkState;
diff --git a/LibGUI/GTextBox.h b/LibGUI/GTextBox.h
index 779d3b9734..552f66bb57 100644
--- a/LibGUI/GTextBox.h
+++ b/LibGUI/GTextBox.h
@@ -9,18 +9,18 @@ public:
     virtual ~GTextBox() override;
 
     String text() const { return m_text; }
-    void setText(String&&);
+    void set_text(String&&);
 
     Function<void(GTextBox&)> onReturnPressed;
 
 private:
     virtual const char* class_name() const override { return "GTextBox"; }
-    virtual void paintEvent(GPaintEvent&) override;
-    virtual void mouseDownEvent(GMouseEvent&) override;
-    virtual void keyDownEvent(GKeyEvent&) override;
+    virtual void paint_event(GPaintEvent&) override;
+    virtual void mousedown_event(GMouseEvent&) override;
+    virtual void keydown_event(GKeyEvent&) override;
     virtual void timerEvent(GTimerEvent&) override;
 
-    void handleBackspace();
+    void handle_backspace();
 
     String m_text;
     unsigned m_cursorPosition { 0 };
diff --git a/LibGUI/GWidget.cpp b/LibGUI/GWidget.cpp
index 57236f363f..25fe852f27 100644
--- a/LibGUI/GWidget.cpp
+++ b/LibGUI/GWidget.cpp
@@ -9,19 +9,19 @@
 GWidget::GWidget(GWidget* parent)
     : GObject(parent)
 {
-    setFont(nullptr);
-    m_backgroundColor = Color::White;
-    m_foregroundColor = Color::Black;
+    set_font(nullptr);
+    m_background_color = Color::White;
+    m_foreground_color = Color::Black;
 }
 
 GWidget::~GWidget()
 {
 }
 
-void GWidget::setWindowRelativeRect(const Rect& rect, bool should_update)
+void GWidget::set_relative_rect(const Rect& rect, bool should_update)
 {
     // FIXME: Make some kind of event loop driven ResizeEvent?
-    m_relativeRect = rect;
+    m_relative_rect = rect;
     if (should_update)
         update();
 }
@@ -35,33 +35,33 @@ void GWidget::event(GEvent& event)
 {
     switch (event.type()) {
     case GEvent::Paint:
-        m_hasPendingPaintEvent = false;
-        return paintEvent(static_cast<GPaintEvent&>(event));
+        m_has_pending_paint_event = false;
+        return paint_event(static_cast<GPaintEvent&>(event));
     case GEvent::Show:
-        return showEvent(static_cast<GShowEvent&>(event));
+        return show_event(static_cast<GShowEvent&>(event));
     case GEvent::Hide:
-        return hideEvent(static_cast<GHideEvent&>(event));
+        return hide_event(static_cast<GHideEvent&>(event));
     case GEvent::KeyDown:
-        return keyDownEvent(static_cast<GKeyEvent&>(event));
+        return keydown_event(static_cast<GKeyEvent&>(event));
     case GEvent::KeyUp:
-        return keyUpEvent(static_cast<GKeyEvent&>(event));
+        return keyup_event(static_cast<GKeyEvent&>(event));
     case GEvent::MouseMove:
-        return mouseMoveEvent(static_cast<GMouseEvent&>(event));
+        return mousemove_event(static_cast<GMouseEvent&>(event));
     case GEvent::MouseDown:
         // FIXME: Focus self if needed.
-        return mouseDownEvent(static_cast<GMouseEvent&>(event));
+        return mousedown_event(static_cast<GMouseEvent&>(event));
     case GEvent::MouseUp:
-        return mouseUpEvent(static_cast<GMouseEvent&>(event));
+        return mouseup_event(static_cast<GMouseEvent&>(event));
     default:
         return GObject::event(event);
     }
 }
 
-void GWidget::paintEvent(GPaintEvent& event)
+void GWidget::paint_event(GPaintEvent& event)
 {
-    if (fillWithBackgroundColor()) {
+    if (fill_with_background_color()) {
         Painter painter(*this);
-        painter.fill_rect(event.rect(), backgroundColor());
+        painter.fill_rect(event.rect(), background_color());
     }
     for (auto* ch : children()) {
         auto* child = (GWidget*)ch;
@@ -69,31 +69,31 @@ void GWidget::paintEvent(GPaintEvent& event)
     }
 }
 
-void GWidget::showEvent(GShowEvent&)
+void GWidget::show_event(GShowEvent&)
 {
 }
 
-void GWidget::hideEvent(GHideEvent&)
+void GWidget::hide_event(GHideEvent&)
 {
 }
 
-void GWidget::keyDownEvent(GKeyEvent&)
+void GWidget::keydown_event(GKeyEvent&)
 {
 }
 
-void GWidget::keyUpEvent(GKeyEvent&)
+void GWidget::keyup_event(GKeyEvent&)
 {
 }
 
-void GWidget::mouseDownEvent(GMouseEvent&)
+void GWidget::mousedown_event(GMouseEvent&)
 {
 }
 
-void GWidget::mouseUpEvent(GMouseEvent&)
+void GWidget::mouseup_event(GMouseEvent&)
 {
 }
 
-void GWidget::mouseMoveEvent(GMouseEvent&)
+void GWidget::mousemove_event(GMouseEvent&)
 {
 }
 
@@ -102,19 +102,19 @@ void GWidget::update()
     auto* w = window();
     if (!w)
         return;
-    if (m_hasPendingPaintEvent)
+    if (m_has_pending_paint_event)
         return;
-    m_hasPendingPaintEvent = true;
-    GEventLoop::main().post_event(w, make<GPaintEvent>(relativeRect()));
+    m_has_pending_paint_event = true;
+    GEventLoop::main().post_event(w, make<GPaintEvent>(relative_rect()));
 }
 
-GWidget::HitTestResult GWidget::hitTest(int x, int y)
+GWidget::HitTestResult GWidget::hit_test(int x, int y)
 {
     // FIXME: Care about z-order.
     for (auto* ch : children()) {
         auto* child = (GWidget*)ch;
-        if (child->relativeRect().contains(x, y)) {
-            return child->hitTest(x - child->relativeRect().x(), y - child->relativeRect().y());
+        if (child->relative_rect().contains(x, y)) {
+            return child->hit_test(x - child->relative_rect().x(), y - child->relative_rect().y());
         }
     }
     return { this, x, y };
@@ -127,20 +127,20 @@ void GWidget::set_window(GWindow* window)
     m_window = window;
 }
 
-bool GWidget::isFocused() const
+bool GWidget::is_focused() const
 {
     // FIXME: Implement.
     return false;
 }
 
-void GWidget::setFocus(bool focus)
+void GWidget::set_focus(bool focus)
 {
-    if (focus == isFocused())
+    if (focus == is_focused())
         return;
     // FIXME: Implement.
 }
 
-void GWidget::setFont(RetainPtr<Font>&& font)
+void GWidget::set_font(RetainPtr<Font>&& font)
 {
     if (!font)
         m_font = Font::default_font();
diff --git a/LibGUI/GWidget.h b/LibGUI/GWidget.h
index ee02ce50b8..70826a2bcd 100644
--- a/LibGUI/GWidget.h
+++ b/LibGUI/GWidget.h
@@ -13,87 +13,87 @@ class GWindow;
 class GWidget : public GObject {
 public:
     explicit GWidget(GWidget* parent = nullptr);
-    virtual ~GWidget();
+    virtual ~GWidget() override;
 
     virtual void event(GEvent&) override;
-    virtual void paintEvent(GPaintEvent&);
-    virtual void showEvent(GShowEvent&);
-    virtual void hideEvent(GHideEvent&);
-    virtual void keyDownEvent(GKeyEvent&);
-    virtual void keyUpEvent(GKeyEvent&);
-    virtual void mouseMoveEvent(GMouseEvent&);
-    virtual void mouseDownEvent(GMouseEvent&);
-    virtual void mouseUpEvent(GMouseEvent&);
+    virtual void paint_event(GPaintEvent&);
+    virtual void show_event(GShowEvent&);
+    virtual void hide_event(GHideEvent&);
+    virtual void keydown_event(GKeyEvent&);
+    virtual void keyup_event(GKeyEvent&);
+    virtual void mousemove_event(GMouseEvent&);
+    virtual void mousedown_event(GMouseEvent&);
+    virtual void mouseup_event(GMouseEvent&);
 
-    Rect relativeRect() const { return m_relativeRect; }
-    Point relativePosition() const { return m_relativeRect.location(); }
+    Rect relative_rect() const { return m_relative_rect; }
+    Point relative_position() const { return m_relative_rect.location(); }
 
-    int x() const { return m_relativeRect.x(); }
-    int y() const { return m_relativeRect.y(); }
-    int width() const { return m_relativeRect.width(); }
-    int height() const { return m_relativeRect.height(); }
+    int x() const { return m_relative_rect.x(); }
+    int y() const { return m_relative_rect.y(); }
+    int width() const { return m_relative_rect.width(); }
+    int height() const { return m_relative_rect.height(); }
 
     Rect rect() const { return { 0, 0, width(), height() }; }
-    Size size() const { return m_relativeRect.size(); }
+    Size size() const { return m_relative_rect.size(); }
 
     void update();
     void repaint(const Rect&);
 
-    bool isFocused() const;
-    void setFocus(bool);
+    bool is_focused() const;
+    void set_focus(bool);
 
     struct HitTestResult {
         GWidget* widget { nullptr };
         int localX { 0 };
         int localY { 0 };
     };
-    HitTestResult hitTest(int x, int y);
+    HitTestResult hit_test(int x, int y);
 
     virtual const char* class_name() const override { return "GWidget"; }
 
-    void setWindowRelativeRect(const Rect&, bool should_update = true);
+    void set_relative_rect(const Rect&, bool should_update = true);
 
-    Color backgroundColor() const { return m_backgroundColor; }
-    Color foregroundColor() const { return m_foregroundColor; }
+    Color background_color() const { return m_background_color; }
+    Color foreground_color() const { return m_foreground_color; }
 
-    void setBackgroundColor(Color color) { m_backgroundColor = color; }
-    void setForegroundColor(Color color) { m_foregroundColor = color; }
+    void set_background_color(Color color) { m_background_color = color; }
+    void set_foreground_color(Color color) { m_foreground_color = color; }
 
     GWindow* window()
     {
-        if (auto* pw = parentWidget())
+        if (auto* pw = parent_widget())
             return pw->window();
         return m_window;
     }
 
     const GWindow* window() const
     {
-        if (auto* pw = parentWidget())
+        if (auto* pw = parent_widget())
             return pw->window();
         return m_window;
     }
 
     void set_window(GWindow*);
 
-    GWidget* parentWidget() { return static_cast<GWidget*>(parent()); }
-    const GWidget* parentWidget() const { return static_cast<const GWidget*>(parent()); }
+    GWidget* parent_widget() { return static_cast<GWidget*>(parent()); }
+    const GWidget* parent_widget() const { return static_cast<const GWidget*>(parent()); }
 
-    void setFillWithBackgroundColor(bool b) { m_fillWithBackgroundColor = b; }
-    bool fillWithBackgroundColor() const { return m_fillWithBackgroundColor; }
+    void set_fill_with_background_color(bool b) { m_fill_with_background_color = b; }
+    bool fill_with_background_color() const { return m_fill_with_background_color; }
 
     const Font& font() const { return *m_font; }
-    void setFont(RetainPtr<Font>&&);
+    void set_font(RetainPtr<Font>&&);
 
     GraphicsBitmap* backing();
 
 private:
     GWindow* m_window { nullptr };
 
-    Rect m_relativeRect;
-    Color m_backgroundColor { 0xffffff };
-    Color m_foregroundColor { 0x000000 };
+    Rect m_relative_rect;
+    Color m_background_color { 0xffffff };
+    Color m_foreground_color { 0x000000 };
     RetainPtr<Font> m_font;
 
-    bool m_hasPendingPaintEvent { false };
-    bool m_fillWithBackgroundColor { true };
+    bool m_has_pending_paint_event { false };
+    bool m_fill_with_background_color { true };
 };
diff --git a/LibGUI/GWindow.cpp b/LibGUI/GWindow.cpp
index 53899e45ec..1131b82910 100644
--- a/LibGUI/GWindow.cpp
+++ b/LibGUI/GWindow.cpp
@@ -91,7 +91,7 @@ void GWindow::event(GEvent& event)
             return;
         auto& mouse_event = static_cast<GMouseEvent&>(event);
         if (m_main_widget) {
-            auto result = m_main_widget->hitTest(mouse_event.x(), mouse_event.y());
+            auto result = m_main_widget->hit_test(mouse_event.x(), mouse_event.y());
             auto local_event = make<GMouseEvent>(event.type(), Point { result.localX, result.localY }, mouse_event.buttons(), mouse_event.button());
             ASSERT(result.widget);
             return result.widget->event(*local_event);
diff --git a/SharedGraphics/Painter.cpp b/SharedGraphics/Painter.cpp
index 59987601e0..94aaee364b 100644
--- a/SharedGraphics/Painter.cpp
+++ b/SharedGraphics/Painter.cpp
@@ -25,13 +25,13 @@ Painter::Painter(GWidget& widget)
     m_target = widget.backing();
     ASSERT(m_target);
     m_window = widget.window();
-    m_translation.move_by(widget.relativePosition());
+    m_translation.move_by(widget.relative_position());
     // NOTE: m_clip_rect is in Window coordinates since we are painting into its backing store.
-    m_clip_rect = widget.relativeRect();
+    m_clip_rect = widget.relative_rect();
 
 #ifdef DEBUG_WIDGET_UNDERDRAW
     // If the widget is not opaque, let's not mess it up with debugging color.
-    if (widget.fillWithBackgroundColor() && m_window->main_widget() != &widget)
+    if (widget.fill_with_background_color() && m_window->main_widget() != &widget)
         fill_rect(widget.rect(), Color::Red);
 #endif
 }
diff --git a/Userland/guitest2.cpp b/Userland/guitest2.cpp
index 0244d20e86..e9de8788ab 100644
--- a/Userland/guitest2.cpp
+++ b/Userland/guitest2.cpp
@@ -36,23 +36,23 @@ GWindow* make_font_test_window()
 
     auto* widget = new GWidget;
     window->set_main_widget(widget);
-    widget->setWindowRelativeRect({ 0, 0, 300, 80 });
+    widget->set_relative_rect({ 0, 0, 300, 80 });
 
     auto* l1 = new GLabel(widget);
-    l1->setWindowRelativeRect({ 0, 0, 300, 20 });
-    l1->setText("0123456789");
+    l1->set_relative_rect({ 0, 0, 300, 20 });
+    l1->set_text("0123456789");
 
     auto* l2 = new GLabel(widget);
-    l2->setWindowRelativeRect({ 0, 20, 300, 20 });
-    l2->setText("ABCDEFGHIJKLMNOPQRSTUVWXYZ");
+    l2->set_relative_rect({ 0, 20, 300, 20 });
+    l2->set_text("ABCDEFGHIJKLMNOPQRSTUVWXYZ");
 
     auto* l3 = new GLabel(widget);
-    l3->setWindowRelativeRect({ 0, 40, 300, 20 });
-    l3->setText("abcdefghijklmnopqrstuvwxyz");
+    l3->set_relative_rect({ 0, 40, 300, 20 });
+    l3->set_text("abcdefghijklmnopqrstuvwxyz");
 
     auto* l4 = new GLabel(widget);
-    l4->setWindowRelativeRect({ 0, 60, 300, 20 });
-    l4->setText("!\"#$%&'()*+,-./:;<=>?@[\\]^_{|}~");
+    l4->set_relative_rect({ 0, 60, 300, 20 });
+    l4->set_text("!\"#$%&'()*+,-./:;<=>?@[\\]^_{|}~");
 
     return window;
 }
@@ -65,14 +65,14 @@ GWindow* make_launcher_window()
 
     auto* widget = new GWidget;
     window->set_main_widget(widget);
-    widget->setWindowRelativeRect({ 0, 0, 80, 200 });
+    widget->set_relative_rect({ 0, 0, 80, 200 });
 
     auto* label = new GLabel(widget);
-    label->setWindowRelativeRect({ 0, 0, 80, 20 });
-    label->setText("Apps");
+    label->set_relative_rect({ 0, 0, 80, 20 });
+    label->set_text("Apps");
 
     auto* button = new GButton(widget);
-    button->setWindowRelativeRect({ 5, 20, 70, 20 });
+    button->set_relative_rect({ 5, 20, 70, 20 });
     button->set_caption("Terminal");
 
     button->on_click = [] (GButton&) {