diff --git a/UI/Qt/BrowserWindow.cpp b/UI/Qt/BrowserWindow.cpp
index 485d0d112a..5cd33dd7d4 100644
--- a/UI/Qt/BrowserWindow.cpp
+++ b/UI/Qt/BrowserWindow.cpp
@@ -43,6 +43,7 @@
 #include <QMenuBar>
 #include <QMessageBox>
 #include <QMouseEvent>
+#include <QPainter>
 #include <QPlatformSurfaceEvent>
 #include <QPropertyAnimation>
 #include <QPushButton>
@@ -242,6 +243,7 @@ BrowserWindow::BrowserWindow(Vector<URL::URL> const& initial_urls, IsPopupWindow
     setWindowIcon(app_icon());
     qApp->installEventFilter(this);
     update_window_corners();
+    update_window_border();
 
     update_tabs_display();
 
@@ -979,6 +981,7 @@ void BrowserWindow::update_window_decoration_state()
     }
 
     update_menu_bar_visibility();
+    update_window_border();
 }
 
 void BrowserWindow::toggle_window_maximized()
@@ -1317,6 +1320,7 @@ void BrowserWindow::changeEvent(QEvent* event)
         update_menu_bar_window_control_icons();
         m_tabs_container->update_window_button_icons();
         update_window_corners();
+        update_window_border();
 
         QWindowStateChangeEvent* stateChangeEvent = static_cast<QWindowStateChangeEvent*>(event);
         bool was_fullscreen = stateChangeEvent->oldState() & Qt::WindowFullScreen;
@@ -1357,6 +1361,39 @@ void BrowserWindow::update_window_corners()
 #endif
 }
 
+bool BrowserWindow::should_draw_window_border() const
+{
+#if defined(AK_OS_MACOS)
+    // macOS frameless windows already get rounded corners and a native shadow, so a painted border would clash.
+    return false;
+#else
+    return windowFlags().testFlag(Qt::FramelessWindowHint) && !isFullScreen() && !isMaximized();
+#endif
+}
+
+void BrowserWindow::update_window_border()
+{
+    auto border_width = should_draw_window_border() ? 1 : 0;
+    setContentsMargins(border_width, border_width, border_width, border_width);
+    update();
+}
+
+void BrowserWindow::paintEvent(QPaintEvent* event)
+{
+    QMainWindow::paintEvent(event);
+
+    if (!should_draw_window_border())
+        return;
+
+    QPainter painter(this);
+    auto color = ChromeStyle::chrome_window_outline(palette());
+    auto frame = rect();
+    painter.fillRect(QRect(frame.left(), frame.top(), frame.width(), 1), color);
+    painter.fillRect(QRect(frame.left(), frame.bottom(), frame.width(), 1), color);
+    painter.fillRect(QRect(frame.left(), frame.top(), 1, frame.height()), color);
+    painter.fillRect(QRect(frame.right(), frame.top(), 1, frame.height()), color);
+}
+
 void BrowserWindow::moveEvent(QMoveEvent* event)
 {
     QWidget::moveEvent(event);
diff --git a/UI/Qt/BrowserWindow.h b/UI/Qt/BrowserWindow.h
index 1b88b37be0..0785016be2 100644
--- a/UI/Qt/BrowserWindow.h
+++ b/UI/Qt/BrowserWindow.h
@@ -153,6 +153,7 @@ private:
     virtual void resizeEvent(QResizeEvent*) override;
     virtual void changeEvent(QEvent* event) override;
     virtual void moveEvent(QMoveEvent*) override;
+    virtual void paintEvent(QPaintEvent*) override;
     virtual void wheelEvent(QWheelEvent*) override;
     virtual void closeEvent(QCloseEvent*) override;
 
@@ -170,6 +171,8 @@ private:
     void update_resize_cursor(QPoint const&);
     void clear_resize_cursor();
     void update_window_corners();
+    bool should_draw_window_border() const;
+    void update_window_border();
 
     template<typename Callback>
     void for_each_tab(Callback&& callback)
diff --git a/UI/Qt/ChromeStyle.cpp b/UI/Qt/ChromeStyle.cpp
index 297e1fd3a5..fc8bc31baf 100644
--- a/UI/Qt/ChromeStyle.cpp
+++ b/UI/Qt/ChromeStyle.cpp
@@ -203,6 +203,17 @@ QColor chrome_border(QPalette const& palette)
     return mix(dark ? chrome_surface(palette) : chrome_background(palette), material_color_anchors(dark).border, 0.22);
 }
 
+QColor chrome_window_outline(QPalette const& palette)
+{
+    auto dark = is_dark(palette);
+    if (dark)
+        return chrome_border(palette);
+
+    // The window outline has to hold up against arbitrary backdrops behind the window, not just our own chrome
+    // surfaces, so in light mode it is mixed further toward the border anchor than chrome_border().
+    return mix(chrome_background(palette), material_color_anchors(false).border, 0.5);
+}
+
 QColor chrome_accent(QPalette const& palette)
 {
     return palette.color(QPalette::Highlight);
diff --git a/UI/Qt/ChromeStyle.h b/UI/Qt/ChromeStyle.h
index 6245a4a280..aeac46745e 100644
--- a/UI/Qt/ChromeStyle.h
+++ b/UI/Qt/ChromeStyle.h
@@ -25,6 +25,7 @@ QColor chrome_control_border(QPalette const&);
 QColor chrome_active_tab_surface_top(QPalette const&);
 QColor chrome_active_tab_surface_bottom(QPalette const&);
 QColor chrome_border(QPalette const&);
+QColor chrome_window_outline(QPalette const&);
 QColor chrome_accent(QPalette const&);
 QColor chrome_muted_text(QPalette const&);