diff --git a/Base/res/html/misc/mouse-events.html b/Base/res/html/misc/mouse-events.html
index ed6d04fc7eb..a1cd440db78 100644
--- a/Base/res/html/misc/mouse-events.html
+++ b/Base/res/html/misc/mouse-events.html
@@ -10,7 +10,7 @@
 <script>
 function handle(e) {
     var out = document.getElementById('out');
-    out.innerHTML = `${e.type} | client: ${e.clientX}x${e.y} | screen: ${e.screenX}x${e.screenY}\n${out.innerHTML}`;
+    out.innerHTML = `${e.type} | client: ${e.clientX}x${e.y} | screen: ${e.screenX}x${e.screenY} | ${e.ctrlKey ? 'CTRL' : ''} ${e.shiftKey ? 'Shift' : ''} ${e.altKey ? 'Alt' : ''}\n${out.innerHTML}`;
 }
 
 var rect = document.getElementById('rect');
diff --git a/Userland/Libraries/LibWeb/Page/EventHandler.cpp b/Userland/Libraries/LibWeb/Page/EventHandler.cpp
index c5ddf63a6aa..49e4875c9b2 100644
--- a/Userland/Libraries/LibWeb/Page/EventHandler.cpp
+++ b/Userland/Libraries/LibWeb/Page/EventHandler.cpp
@@ -189,7 +189,7 @@ bool EventHandler::handle_mousewheel(CSSPixelPoint position, CSSPixelPoint scree
             auto offset = compute_mouse_event_offset(position, *layout_node);
             auto client_offset = compute_mouse_event_client_offset(position);
             auto page_offset = compute_mouse_event_page_offset(client_offset);
-            if (node->dispatch_event(UIEvents::WheelEvent::create_from_platform_event(node->realm(), UIEvents::EventNames::wheel, screen_position, page_offset, client_offset, offset, wheel_delta_x, wheel_delta_y, button, buttons).release_value_but_fixme_should_propagate_errors())) {
+            if (node->dispatch_event(UIEvents::WheelEvent::create_from_platform_event(node->realm(), UIEvents::EventNames::wheel, screen_position, page_offset, client_offset, offset, wheel_delta_x, wheel_delta_y, button, buttons, modifiers).release_value_but_fixme_should_propagate_errors())) {
                 if (auto* page = m_browsing_context->page()) {
                     if (m_browsing_context == &page->top_level_browsing_context())
                         page->client().page_did_request_scroll(wheel_delta_x, wheel_delta_y);
@@ -250,15 +250,15 @@ bool EventHandler::handle_mouseup(CSSPixelPoint position, CSSPixelPoint screen_p
             auto offset = compute_mouse_event_offset(position, *layout_node);
             auto client_offset = compute_mouse_event_client_offset(position);
             auto page_offset = compute_mouse_event_page_offset(client_offset);
-            node->dispatch_event(UIEvents::MouseEvent::create_from_platform_event(node->realm(), UIEvents::EventNames::mouseup, screen_position, page_offset, client_offset, offset, {}, button, buttons).release_value_but_fixme_should_propagate_errors());
+            node->dispatch_event(UIEvents::MouseEvent::create_from_platform_event(node->realm(), UIEvents::EventNames::mouseup, screen_position, page_offset, client_offset, offset, {}, button, buttons, modifiers).release_value_but_fixme_should_propagate_errors());
             handled_event = true;
 
             bool run_activation_behavior = false;
             if (node.ptr() == m_mousedown_target) {
                 if (button == GUI::MouseButton::Primary)
-                    run_activation_behavior = node->dispatch_event(UIEvents::MouseEvent::create_from_platform_event(node->realm(), UIEvents::EventNames::click, screen_position, page_offset, client_offset, offset, {}, 1, button).release_value_but_fixme_should_propagate_errors());
+                    run_activation_behavior = node->dispatch_event(UIEvents::MouseEvent::create_from_platform_event(node->realm(), UIEvents::EventNames::click, screen_position, page_offset, client_offset, offset, {}, 1, button, modifiers).release_value_but_fixme_should_propagate_errors());
                 else if (button == GUI::MouseButton::Secondary && !(modifiers & Mod_Shift)) // Allow the user to bypass custom context menus by holding shift, like Firefox.
-                    run_activation_behavior = node->dispatch_event(UIEvents::MouseEvent::create_from_platform_event(node->realm(), UIEvents::EventNames::contextmenu, screen_position, page_offset, client_offset, offset, {}, 1, button).release_value_but_fixme_should_propagate_errors());
+                    run_activation_behavior = node->dispatch_event(UIEvents::MouseEvent::create_from_platform_event(node->realm(), UIEvents::EventNames::contextmenu, screen_position, page_offset, client_offset, offset, {}, 1, button, modifiers).release_value_but_fixme_should_propagate_errors());
             }
 
             if (run_activation_behavior) {
@@ -386,7 +386,7 @@ bool EventHandler::handle_mousedown(CSSPixelPoint position, CSSPixelPoint screen
         auto offset = compute_mouse_event_offset(position, *layout_node);
         auto client_offset = compute_mouse_event_client_offset(position);
         auto page_offset = compute_mouse_event_page_offset(client_offset);
-        node->dispatch_event(UIEvents::MouseEvent::create_from_platform_event(node->realm(), UIEvents::EventNames::mousedown, screen_position, page_offset, client_offset, offset, {}, button, buttons).release_value_but_fixme_should_propagate_errors());
+        node->dispatch_event(UIEvents::MouseEvent::create_from_platform_event(node->realm(), UIEvents::EventNames::mousedown, screen_position, page_offset, client_offset, offset, {}, button, buttons, modifiers).release_value_but_fixme_should_propagate_errors());
     }
 
     // NOTE: Dispatching an event may have disturbed the world.
@@ -500,7 +500,7 @@ bool EventHandler::handle_mousemove(CSSPixelPoint position, CSSPixelPoint screen
             auto client_offset = compute_mouse_event_client_offset(position);
             auto page_offset = compute_mouse_event_page_offset(client_offset);
             auto movement = compute_mouse_event_movement(screen_position);
-            node->dispatch_event(UIEvents::MouseEvent::create_from_platform_event(node->realm(), UIEvents::EventNames::mousemove, screen_position, page_offset, client_offset, offset, movement, 1, buttons).release_value_but_fixme_should_propagate_errors());
+            node->dispatch_event(UIEvents::MouseEvent::create_from_platform_event(node->realm(), UIEvents::EventNames::mousemove, screen_position, page_offset, client_offset, offset, movement, 1, buttons, modifiers).release_value_but_fixme_should_propagate_errors());
             m_mousemove_previous_screen_position = screen_position;
             // NOTE: Dispatching an event may have disturbed the world.
             if (!paint_root() || paint_root() != node->document().paintable_box())
@@ -586,7 +586,7 @@ bool EventHandler::handle_doubleclick(CSSPixelPoint position, CSSPixelPoint scre
     auto offset = compute_mouse_event_offset(position, *layout_node);
     auto client_offset = compute_mouse_event_client_offset(position);
     auto page_offset = compute_mouse_event_page_offset(client_offset);
-    node->dispatch_event(UIEvents::MouseEvent::create_from_platform_event(node->realm(), UIEvents::EventNames::dblclick, screen_position, page_offset, client_offset, offset, {}, button, buttons).release_value_but_fixme_should_propagate_errors());
+    node->dispatch_event(UIEvents::MouseEvent::create_from_platform_event(node->realm(), UIEvents::EventNames::dblclick, screen_position, page_offset, client_offset, offset, {}, button, buttons, modifiers).release_value_but_fixme_should_propagate_errors());
 
     // NOTE: Dispatching an event may have disturbed the world.
     if (!paint_root() || paint_root() != node->document().paintable_box())
diff --git a/Userland/Libraries/LibWeb/UIEvents/KeyboardEvent.cpp b/Userland/Libraries/LibWeb/UIEvents/KeyboardEvent.cpp
index 5e4bbc24c3e..7834a25e682 100644
--- a/Userland/Libraries/LibWeb/UIEvents/KeyboardEvent.cpp
+++ b/Userland/Libraries/LibWeb/UIEvents/KeyboardEvent.cpp
@@ -516,7 +516,7 @@ JS::NonnullGCPtr<KeyboardEvent> KeyboardEvent::create_from_platform_event(JS::Re
     event_init.ctrl_key = modifiers & Mod_Ctrl;
     event_init.shift_key = modifiers & Mod_Shift;
     event_init.alt_key = modifiers & Mod_Alt;
-    event_init.meta_key = false;
+    event_init.meta_key = false; // FIXME: Implement meta key
     event_init.repeat = false;
     event_init.is_composing = false;
     event_init.key_code = key_code;
diff --git a/Userland/Libraries/LibWeb/UIEvents/MouseEvent.cpp b/Userland/Libraries/LibWeb/UIEvents/MouseEvent.cpp
index 6b822c2c105..03a7ecc6b70 100644
--- a/Userland/Libraries/LibWeb/UIEvents/MouseEvent.cpp
+++ b/Userland/Libraries/LibWeb/UIEvents/MouseEvent.cpp
@@ -5,6 +5,7 @@
  * SPDX-License-Identifier: BSD-2-Clause
  */
 
+#include <Kernel/API/KeyCode.h>
 #include <LibGUI/Event.h>
 #include <LibWeb/Bindings/Intrinsics.h>
 #include <LibWeb/HTML/EventNames.h>
@@ -13,7 +14,7 @@
 
 namespace Web::UIEvents {
 
-MouseEvent::MouseEvent(JS::Realm& realm, FlyString const& event_name, MouseEventInit const& event_init, double page_x, double page_y, double offset_x, double offset_y)
+MouseEvent::MouseEvent(JS::Realm& realm, FlyString const& event_name, MouseEventInit const& event_init, double page_x, double page_y, double offset_x, double offset_y, unsigned modifiers)
     : UIEvent(realm, event_name, event_init)
     , m_screen_x(event_init.screen_x)
     , m_screen_y(event_init.screen_y)
@@ -23,6 +24,10 @@ MouseEvent::MouseEvent(JS::Realm& realm, FlyString const& event_name, MouseEvent
     , m_client_y(event_init.client_y)
     , m_offset_x(offset_x)
     , m_offset_y(offset_y)
+    , m_ctrl_key(modifiers & Mod_Ctrl)
+    , m_shift_key(modifiers & Mod_Shift)
+    , m_alt_key(modifiers & Mod_Alt)
+    , m_meta_key(false) // FIXME: Implement meta key
     , m_movement_x(event_init.movement_x)
     , m_movement_y(event_init.movement_y)
     , m_button(event_init.button)
@@ -58,12 +63,12 @@ static i16 determine_button(unsigned mouse_button)
     }
 }
 
-JS::NonnullGCPtr<MouseEvent> MouseEvent::create(JS::Realm& realm, FlyString const& event_name, MouseEventInit const& event_init, double page_x, double page_y, double offset_x, double offset_y)
+JS::NonnullGCPtr<MouseEvent> MouseEvent::create(JS::Realm& realm, FlyString const& event_name, MouseEventInit const& event_init, double page_x, double page_y, double offset_x, double offset_y, unsigned modifiers)
 {
-    return realm.heap().allocate<MouseEvent>(realm, realm, event_name, event_init, page_x, page_y, offset_x, offset_y);
+    return realm.heap().allocate<MouseEvent>(realm, realm, event_name, event_init, page_x, page_y, offset_x, offset_y, modifiers);
 }
 
-WebIDL::ExceptionOr<JS::NonnullGCPtr<MouseEvent>> MouseEvent::create_from_platform_event(JS::Realm& realm, FlyString const& event_name, CSSPixelPoint screen, CSSPixelPoint page, CSSPixelPoint client, CSSPixelPoint offset, Optional<CSSPixelPoint> movement, unsigned button, unsigned buttons)
+WebIDL::ExceptionOr<JS::NonnullGCPtr<MouseEvent>> MouseEvent::create_from_platform_event(JS::Realm& realm, FlyString const& event_name, CSSPixelPoint screen, CSSPixelPoint page, CSSPixelPoint client, CSSPixelPoint offset, Optional<CSSPixelPoint> movement, unsigned button, unsigned buttons, unsigned modifiers)
 {
     MouseEventInit event_init {};
     event_init.screen_x = screen.x().to_double();
@@ -76,7 +81,7 @@ WebIDL::ExceptionOr<JS::NonnullGCPtr<MouseEvent>> MouseEvent::create_from_platfo
     }
     event_init.button = determine_button(button);
     event_init.buttons = buttons;
-    return MouseEvent::create(realm, event_name, event_init, page.x().to_double(), page.y().to_double(), offset.x().to_double(), offset.y().to_double());
+    return MouseEvent::create(realm, event_name, event_init, page.x().to_double(), page.y().to_double(), offset.x().to_double(), offset.y().to_double(), modifiers);
 }
 
 void MouseEvent::set_event_characteristics()
diff --git a/Userland/Libraries/LibWeb/UIEvents/MouseEvent.h b/Userland/Libraries/LibWeb/UIEvents/MouseEvent.h
index be2d4a6e994..e1b41fe2d6f 100644
--- a/Userland/Libraries/LibWeb/UIEvents/MouseEvent.h
+++ b/Userland/Libraries/LibWeb/UIEvents/MouseEvent.h
@@ -28,8 +28,8 @@ class MouseEvent : public UIEvent {
     WEB_PLATFORM_OBJECT(MouseEvent, UIEvent);
 
 public:
-    [[nodiscard]] static JS::NonnullGCPtr<MouseEvent> create(JS::Realm&, FlyString const& event_name, MouseEventInit const& = {}, double page_x = 0, double page_y = 0, double offset_x = 0, double offset_y = 0);
-    static WebIDL::ExceptionOr<JS::NonnullGCPtr<MouseEvent>> create_from_platform_event(JS::Realm&, FlyString const& event_name, CSSPixelPoint screen, CSSPixelPoint page, CSSPixelPoint client, CSSPixelPoint offset, Optional<CSSPixelPoint> movement, unsigned button, unsigned buttons);
+    [[nodiscard]] static JS::NonnullGCPtr<MouseEvent> create(JS::Realm&, FlyString const& event_name, MouseEventInit const& = {}, double page_x = 0, double page_y = 0, double offset_x = 0, double offset_y = 0, unsigned modifiers = 0);
+    static WebIDL::ExceptionOr<JS::NonnullGCPtr<MouseEvent>> create_from_platform_event(JS::Realm&, FlyString const& event_name, CSSPixelPoint screen, CSSPixelPoint page, CSSPixelPoint client, CSSPixelPoint offset, Optional<CSSPixelPoint> movement, unsigned button, unsigned buttons, unsigned modifiers);
 
     virtual ~MouseEvent() override;
 
@@ -48,6 +48,11 @@ public:
     double offset_x() const { return m_offset_x; }
     double offset_y() const { return m_offset_y; }
 
+    bool ctrl_key() const { return m_ctrl_key; }
+    bool shift_key() const { return m_shift_key; }
+    bool alt_key() const { return m_alt_key; }
+    bool meta_key() const { return m_meta_key; }
+
     double movement_x() const { return m_movement_x; }
     double movement_y() const { return m_movement_y; }
 
@@ -57,7 +62,7 @@ public:
     virtual u32 which() const override { return m_button + 1; }
 
 protected:
-    MouseEvent(JS::Realm&, FlyString const& event_name, MouseEventInit const& event_init, double page_x, double page_y, double offset_x, double offset_y);
+    MouseEvent(JS::Realm&, FlyString const& event_name, MouseEventInit const& event_init, double page_x, double page_y, double offset_x, double offset_y, unsigned modifiers);
 
     virtual void initialize(JS::Realm&) override;
 
@@ -72,6 +77,10 @@ private:
     double m_client_y { 0 };
     double m_offset_x { 0 };
     double m_offset_y { 0 };
+    bool m_ctrl_key { false };
+    bool m_shift_key { false };
+    bool m_alt_key { false };
+    bool m_meta_key { false };
     double m_movement_x { 0 };
     double m_movement_y { 0 };
     i16 m_button { 0 };
diff --git a/Userland/Libraries/LibWeb/UIEvents/MouseEvent.idl b/Userland/Libraries/LibWeb/UIEvents/MouseEvent.idl
index b702457f222..378a54492e9 100644
--- a/Userland/Libraries/LibWeb/UIEvents/MouseEvent.idl
+++ b/Userland/Libraries/LibWeb/UIEvents/MouseEvent.idl
@@ -15,10 +15,10 @@ interface MouseEvent : UIEvent {
     readonly attribute double offsetX;
     readonly attribute double offsetY;
 
-    // FIXME: readonly attribute boolean ctrlKey;
-    // FIXME: readonly attribute boolean shiftKey;
-    // FIXME: readonly attribute boolean altKey;
-    // FIXME: readonly attribute boolean metaKey;
+    readonly attribute boolean ctrlKey;
+    readonly attribute boolean shiftKey;
+    readonly attribute boolean altKey;
+    readonly attribute boolean metaKey;
 
     // https://w3c.github.io/pointerlock/#extensions-to-the-mouseevent-interface
     readonly attribute double movementX;
diff --git a/Userland/Libraries/LibWeb/UIEvents/WheelEvent.cpp b/Userland/Libraries/LibWeb/UIEvents/WheelEvent.cpp
index b8234443b57..2dfd88bdcc0 100644
--- a/Userland/Libraries/LibWeb/UIEvents/WheelEvent.cpp
+++ b/Userland/Libraries/LibWeb/UIEvents/WheelEvent.cpp
@@ -12,8 +12,8 @@
 
 namespace Web::UIEvents {
 
-WheelEvent::WheelEvent(JS::Realm& realm, FlyString const& event_name, WheelEventInit const& event_init, double page_x, double page_y, double offset_x, double offset_y)
-    : MouseEvent(realm, event_name, event_init, page_x, page_y, offset_x, offset_y)
+WheelEvent::WheelEvent(JS::Realm& realm, FlyString const& event_name, WheelEventInit const& event_init, double page_x, double page_y, double offset_x, double offset_y, unsigned modifiers)
+    : MouseEvent(realm, event_name, event_init, page_x, page_y, offset_x, offset_y, modifiers)
     , m_delta_x(event_init.delta_x)
     , m_delta_y(event_init.delta_y)
     , m_delta_mode(event_init.delta_mode)
@@ -29,12 +29,12 @@ void WheelEvent::initialize(JS::Realm& realm)
     set_prototype(&Bindings::ensure_web_prototype<Bindings::WheelEventPrototype>(realm, "WheelEvent"));
 }
 
-JS::NonnullGCPtr<WheelEvent> WheelEvent::create(JS::Realm& realm, FlyString const& event_name, WheelEventInit const& event_init, double page_x, double page_y, double offset_x, double offset_y)
+JS::NonnullGCPtr<WheelEvent> WheelEvent::create(JS::Realm& realm, FlyString const& event_name, WheelEventInit const& event_init, double page_x, double page_y, double offset_x, double offset_y, unsigned modifiers)
 {
-    return realm.heap().allocate<WheelEvent>(realm, realm, event_name, event_init, page_x, page_y, offset_x, offset_y);
+    return realm.heap().allocate<WheelEvent>(realm, realm, event_name, event_init, page_x, page_y, offset_x, offset_y, modifiers);
 }
 
-WebIDL::ExceptionOr<JS::NonnullGCPtr<WheelEvent>> WheelEvent::create_from_platform_event(JS::Realm& realm, FlyString const& event_name, CSSPixelPoint screen, CSSPixelPoint page, CSSPixelPoint client, CSSPixelPoint offset, double delta_x, double delta_y, unsigned button, unsigned buttons)
+WebIDL::ExceptionOr<JS::NonnullGCPtr<WheelEvent>> WheelEvent::create_from_platform_event(JS::Realm& realm, FlyString const& event_name, CSSPixelPoint screen, CSSPixelPoint page, CSSPixelPoint client, CSSPixelPoint offset, double delta_x, double delta_y, unsigned button, unsigned buttons, unsigned modifiers)
 {
     WheelEventInit event_init {};
     event_init.screen_x = screen.x().to_double();
@@ -46,7 +46,7 @@ WebIDL::ExceptionOr<JS::NonnullGCPtr<WheelEvent>> WheelEvent::create_from_platfo
     event_init.delta_x = delta_x;
     event_init.delta_y = delta_y;
     event_init.delta_mode = WheelDeltaMode::DOM_DELTA_PIXEL;
-    return WheelEvent::create(realm, event_name, event_init, page.x().to_double(), page.y().to_double(), offset.x().to_double(), offset.y().to_double());
+    return WheelEvent::create(realm, event_name, event_init, page.x().to_double(), page.y().to_double(), offset.x().to_double(), offset.y().to_double(), modifiers);
 }
 
 void WheelEvent::set_event_characteristics()
diff --git a/Userland/Libraries/LibWeb/UIEvents/WheelEvent.h b/Userland/Libraries/LibWeb/UIEvents/WheelEvent.h
index a72bf385ce6..2982770cd18 100644
--- a/Userland/Libraries/LibWeb/UIEvents/WheelEvent.h
+++ b/Userland/Libraries/LibWeb/UIEvents/WheelEvent.h
@@ -29,8 +29,8 @@ class WheelEvent final : public MouseEvent {
     WEB_PLATFORM_OBJECT(WheelEvent, MouseEvent);
 
 public:
-    [[nodiscard]] static JS::NonnullGCPtr<WheelEvent> create(JS::Realm&, FlyString const& event_name, WheelEventInit const& event_init = {}, double page_x = 0, double page_y = 0, double offset_x = 0, double offset_y = 0);
-    static WebIDL::ExceptionOr<JS::NonnullGCPtr<WheelEvent>> create_from_platform_event(JS::Realm&, FlyString const& event_name, CSSPixelPoint screen, CSSPixelPoint page, CSSPixelPoint client, CSSPixelPoint offset, double delta_x, double delta_y, unsigned button, unsigned buttons);
+    [[nodiscard]] static JS::NonnullGCPtr<WheelEvent> create(JS::Realm&, FlyString const& event_name, WheelEventInit const& event_init = {}, double page_x = 0, double page_y = 0, double offset_x = 0, double offset_y = 0, unsigned modifiers = 0);
+    static WebIDL::ExceptionOr<JS::NonnullGCPtr<WheelEvent>> create_from_platform_event(JS::Realm&, FlyString const& event_name, CSSPixelPoint screen, CSSPixelPoint page, CSSPixelPoint client, CSSPixelPoint offset, double delta_x, double delta_y, unsigned button, unsigned buttons, unsigned modifiers);
 
     virtual ~WheelEvent() override;
 
@@ -40,7 +40,7 @@ public:
     unsigned long delta_mode() const { return to_underlying(m_delta_mode); }
 
 private:
-    WheelEvent(JS::Realm&, FlyString const& event_name, WheelEventInit const& event_init, double page_x, double page_y, double offset_x, double offset_y);
+    WheelEvent(JS::Realm&, FlyString const& event_name, WheelEventInit const& event_init, double page_x, double page_y, double offset_x, double offset_y, unsigned modifiers);
 
     virtual void initialize(JS::Realm&) override;