diff --git a/Libraries/LibWeb/Internals/Internals.cpp b/Libraries/LibWeb/Internals/Internals.cpp
index e1926eacdca..70c23046372 100644
--- a/Libraries/LibWeb/Internals/Internals.cpp
+++ b/Libraries/LibWeb/Internals/Internals.cpp
@@ -244,6 +244,11 @@ void Internals::set_echo_server_port(u16 const port)
     s_echo_server_port = port;
 }
 
+void Internals::set_browser_zoom(double factor)
+{
+    internals_page().client().page_did_set_browser_zoom(factor);
+}
+
 bool Internals::headless()
 {
     return internals_page().client().is_headless();
diff --git a/Libraries/LibWeb/Internals/Internals.h b/Libraries/LibWeb/Internals/Internals.h
index 037e6d4e284..709763e0dff 100644
--- a/Libraries/LibWeb/Internals/Internals.h
+++ b/Libraries/LibWeb/Internals/Internals.h
@@ -56,6 +56,8 @@ public:
     static u16 get_echo_server_port();
     static void set_echo_server_port(u16 port);
 
+    void set_browser_zoom(double factor);
+
     bool headless();
 
 private:
diff --git a/Libraries/LibWeb/Internals/Internals.idl b/Libraries/LibWeb/Internals/Internals.idl
index 19f62a0f894..bdc411ec3bc 100644
--- a/Libraries/LibWeb/Internals/Internals.idl
+++ b/Libraries/LibWeb/Internals/Internals.idl
@@ -45,5 +45,7 @@ interface Internals {
     DOMString getComputedLabel(Element element);
     unsigned short getEchoServerPort();
 
+    undefined setBrowserZoom(double factor);
+
     readonly attribute boolean headless;
 };
diff --git a/Libraries/LibWeb/Page/Page.h b/Libraries/LibWeb/Page/Page.h
index 48540e85318..e709527793b 100644
--- a/Libraries/LibWeb/Page/Page.h
+++ b/Libraries/LibWeb/Page/Page.h
@@ -384,6 +384,8 @@ public:
     virtual void page_did_finish_text_test([[maybe_unused]] String const& text) { }
     virtual void page_did_set_test_timeout([[maybe_unused]] double milliseconds) { }
 
+    virtual void page_did_set_browser_zoom([[maybe_unused]] double factor) { }
+
     virtual void page_did_change_theme_color(Gfx::Color) { }
 
     virtual void page_did_insert_clipboard_entry([[maybe_unused]] String data, [[maybe_unused]] String presentation_style, [[maybe_unused]] String mime_type) { }
diff --git a/Libraries/LibWebView/ViewImplementation.cpp b/Libraries/LibWebView/ViewImplementation.cpp
index dd7467af858..a619274e0db 100644
--- a/Libraries/LibWebView/ViewImplementation.cpp
+++ b/Libraries/LibWebView/ViewImplementation.cpp
@@ -143,6 +143,12 @@ void ViewImplementation::zoom_out()
     update_zoom();
 }
 
+void ViewImplementation::set_zoom(double zoom_level)
+{
+    m_zoom_level = max(ZOOM_MIN_LEVEL, min(zoom_level, ZOOM_MAX_LEVEL));
+    update_zoom();
+}
+
 void ViewImplementation::reset_zoom()
 {
     m_zoom_level = 1.0f;
diff --git a/Libraries/LibWebView/ViewImplementation.h b/Libraries/LibWebView/ViewImplementation.h
index 08581a29eb7..46c91ca38a4 100644
--- a/Libraries/LibWebView/ViewImplementation.h
+++ b/Libraries/LibWebView/ViewImplementation.h
@@ -64,6 +64,7 @@ public:
 
     void zoom_in();
     void zoom_out();
+    void set_zoom(double zoom_level);
     void reset_zoom();
     float zoom_level() const { return m_zoom_level; }
     float device_pixel_ratio() const { return m_device_pixel_ratio; }
@@ -216,6 +217,7 @@ public:
     Function<void(Web::DragEvent const&)> on_finish_handling_drag_event;
     Function<void(String const&)> on_text_test_finish;
     Function<void(double milliseconds)> on_set_test_timeout;
+    Function<void(double factor)> on_set_browser_zoom;
     Function<void(size_t current_match_index, Optional<size_t> const& total_match_count)> on_find_in_page;
     Function<void(Gfx::Color)> on_theme_color_change;
     Function<void(String const&, String const&, String const&)> on_insert_clipboard_entry;
diff --git a/Libraries/LibWebView/WebContentClient.cpp b/Libraries/LibWebView/WebContentClient.cpp
index 19695eb47d0..8bfee313c22 100644
--- a/Libraries/LibWebView/WebContentClient.cpp
+++ b/Libraries/LibWebView/WebContentClient.cpp
@@ -101,6 +101,14 @@ void WebContentClient::did_set_test_timeout(u64 page_id, double milliseconds)
     }
 }
 
+void WebContentClient::did_set_browser_zoom(u64 page_id, double factor)
+{
+    if (auto view = view_for_page_id(page_id); view.has_value()) {
+        if (view->on_set_browser_zoom)
+            view->on_set_browser_zoom(factor);
+    }
+}
+
 void WebContentClient::did_find_in_page(u64 page_id, size_t current_match_index, Optional<size_t> const& total_match_count)
 {
     if (auto view = view_for_page_id(page_id); view.has_value()) {
diff --git a/Libraries/LibWebView/WebContentClient.h b/Libraries/LibWebView/WebContentClient.h
index 7983dea4b9f..acabd17b3da 100644
--- a/Libraries/LibWebView/WebContentClient.h
+++ b/Libraries/LibWebView/WebContentClient.h
@@ -109,6 +109,7 @@ private:
     virtual void did_finish_handling_input_event(u64 page_id, Web::EventResult event_result) override;
     virtual void did_finish_text_test(u64 page_id, String const& text) override;
     virtual void did_set_test_timeout(u64 page_id, double milliseconds) override;
+    virtual void did_set_browser_zoom(u64 page_id, double factor) override;
     virtual void did_find_in_page(u64 page_id, size_t current_match_index, Optional<size_t> const& total_match_count) override;
     virtual void did_change_theme_color(u64 page_id, Gfx::Color color) override;
     virtual void did_insert_clipboard_entry(u64 page_id, String const& data, String const& presentation_style, String const& mime_type) override;
diff --git a/Services/WebContent/PageClient.cpp b/Services/WebContent/PageClient.cpp
index 2a76f117ab2..1b8adf3733d 100644
--- a/Services/WebContent/PageClient.cpp
+++ b/Services/WebContent/PageClient.cpp
@@ -229,6 +229,7 @@ void PageClient::set_viewport_size(Web::DevicePixelSize const& size)
 
     m_backing_store_manager.restart_resize_timer();
     m_backing_store_manager.resize_backing_stores_if_needed(BackingStoreManager::WindowResizingInProgress::Yes);
+    m_pending_set_browser_zoom_request = false;
 }
 
 void PageClient::page_did_request_cursor_change(Gfx::StandardCursor cursor)
@@ -371,6 +372,17 @@ void PageClient::page_did_set_test_timeout(double milliseconds)
     client().async_did_set_test_timeout(m_id, milliseconds);
 }
 
+void PageClient::page_did_set_browser_zoom(double factor)
+{
+    m_pending_set_browser_zoom_request = true;
+    client().async_did_set_browser_zoom(m_id, factor);
+
+    auto& event_loop = Web::HTML::main_thread_event_loop();
+    event_loop.spin_until(GC::create_function(event_loop.heap(), [&]() {
+        return !m_pending_set_browser_zoom_request || !is_connection_open();
+    }));
+}
+
 void PageClient::page_did_request_context_menu(Web::CSSPixelPoint content_position)
 {
     client().async_did_request_context_menu(m_id, page().css_to_device_point(content_position).to_type<int>());
diff --git a/Services/WebContent/PageClient.h b/Services/WebContent/PageClient.h
index f45b6c8c7f8..3a7418d8c40 100644
--- a/Services/WebContent/PageClient.h
+++ b/Services/WebContent/PageClient.h
@@ -159,6 +159,7 @@ private:
     virtual void page_did_request_select_dropdown(Web::CSSPixelPoint content_position, Web::CSSPixels minimum_width, Vector<Web::HTML::SelectItem> items) override;
     virtual void page_did_finish_text_test(String const& text) override;
     virtual void page_did_set_test_timeout(double milliseconds) override;
+    virtual void page_did_set_browser_zoom(double factor) override;
     virtual void page_did_change_theme_color(Gfx::Color color) override;
     virtual void page_did_insert_clipboard_entry(String data, String presentation_style, String mime_type) override;
     virtual void page_did_change_audio_play_state(Web::HTML::AudioPlayState) override;
@@ -215,6 +216,8 @@ private:
     GC::Root<JS::GlobalObject> m_console_global_object;
 
     RefPtr<Core::Timer> m_paint_refresh_timer;
+
+    bool m_pending_set_browser_zoom_request = false;
 };
 
 }
diff --git a/Services/WebContent/WebContentClient.ipc b/Services/WebContent/WebContentClient.ipc
index ffd1eb0a3ac..f74ecf4f77b 100644
--- a/Services/WebContent/WebContentClient.ipc
+++ b/Services/WebContent/WebContentClient.ipc
@@ -97,6 +97,8 @@ endpoint WebContentClient
     did_finish_text_test(u64 page_id, String text) =|
     did_set_test_timeout(u64 page_id, double milliseconds) =|
 
+    did_set_browser_zoom(u64 page_id, double factor) =|
+
     did_find_in_page(u64 page_id, size_t current_match_index, Optional<size_t> total_match_count) =|
 
     request_worker_agent(u64 page_id) => (IPC::File socket) // FIXME: Add required attributes to select a SharedWorker Agent
diff --git a/UI/AppKit/Interface/LadybirdWebView.mm b/UI/AppKit/Interface/LadybirdWebView.mm
index 9d13f894489..64144c57c7b 100644
--- a/UI/AppKit/Interface/LadybirdWebView.mm
+++ b/UI/AppKit/Interface/LadybirdWebView.mm
@@ -958,6 +958,11 @@ static void copy_data_to_clipboard(StringView data, NSPasteboardType pasteboard_
         [NSMenu popUpContextMenu:self.select_dropdown withEvent:event forView:self];
     };
 
+    m_web_view_bridge->on_set_browser_zoom = [](double factor) {
+        (void)factor;
+        dbgln("FIXME: A test called `window.internals.setBrowserZoom()` which is not implemented in the AppKit UI");
+    };
+
     m_web_view_bridge->on_restore_window = [weak_self]() {
         LadybirdWebView* self = weak_self;
         if (self == nil) {
diff --git a/UI/Headless/HeadlessWebView.cpp b/UI/Headless/HeadlessWebView.cpp
index 7b46922bd52..81ef0ba2f74 100644
--- a/UI/Headless/HeadlessWebView.cpp
+++ b/UI/Headless/HeadlessWebView.cpp
@@ -191,4 +191,10 @@ void HeadlessWebView::on_test_complete(TestCompletion completion)
     m_test_promise->resolve(move(completion));
 }
 
+void HeadlessWebView::update_zoom()
+{
+    client().async_set_device_pixels_per_css_pixel(m_client_state.page_index, m_device_pixel_ratio * m_zoom_level);
+    client().async_set_viewport_size(m_client_state.page_index, m_viewport_size);
+}
+
 }
diff --git a/UI/Headless/HeadlessWebView.h b/UI/Headless/HeadlessWebView.h
index c15a614b1af..32eeb788b19 100644
--- a/UI/Headless/HeadlessWebView.h
+++ b/UI/Headless/HeadlessWebView.h
@@ -33,7 +33,7 @@ public:
 private:
     HeadlessWebView(Core::AnonymousBuffer theme, Web::DevicePixelSize viewport_size);
 
-    void update_zoom() override { }
+    void update_zoom() override;
     void initialize_client(CreateNewClient) override;
 
     virtual Web::DevicePixelSize viewport_size() const override { return m_viewport_size; }
diff --git a/UI/Headless/Test.cpp b/UI/Headless/Test.cpp
index 0ddd599a654..01e471a9420 100644
--- a/UI/Headless/Test.cpp
+++ b/UI/Headless/Test.cpp
@@ -140,6 +140,7 @@ void run_dump_test(HeadlessWebView& view, Test& test, URL::URL const& url, int t
         view.on_load_finish = {};
         view.on_text_test_finish = {};
         view.on_set_test_timeout = {};
+        view.reset_zoom();
 
         view.on_test_complete({ test, TestResult::Timeout });
     });
@@ -199,6 +200,7 @@ void run_dump_test(HeadlessWebView& view, Test& test, URL::URL const& url, int t
     };
 
     auto on_test_complete = [&view, &test, timer, handle_completed_test]() {
+        view.reset_zoom();
         clear_test_callbacks(view);
         timer->stop();
 
@@ -268,6 +270,10 @@ void run_dump_test(HeadlessWebView& view, Test& test, URL::URL const& url, int t
         timer->start(milliseconds);
     };
 
+    view.on_set_browser_zoom = [&view](double factor) {
+        view.set_zoom(factor);
+    };
+
     view.load(url);
     timer->start();
 }
@@ -278,6 +284,7 @@ static void run_ref_test(HeadlessWebView& view, Test& test, URL::URL const& url,
         view.on_load_finish = {};
         view.on_text_test_finish = {};
         view.on_set_test_timeout = {};
+        view.reset_zoom();
 
         view.on_test_complete({ test, TestResult::Timeout });
     });
@@ -335,13 +342,15 @@ static void run_ref_test(HeadlessWebView& view, Test& test, URL::URL const& url,
             } else {
                 test.ref_test_expectation_type = RefTestExpectationType::Match;
             }
-            view.take_screenshot()->when_resolved([&test, on_test_complete = move(on_test_complete)](RefPtr<Gfx::Bitmap> screenshot) {
+            view.take_screenshot()->when_resolved([&view, &test, on_test_complete = move(on_test_complete)](RefPtr<Gfx::Bitmap> screenshot) {
                 test.expectation_screenshot = move(screenshot);
+                view.reset_zoom();
                 on_test_complete();
             });
         } else {
             view.take_screenshot()->when_resolved([&view, &test](RefPtr<Gfx::Bitmap> screenshot) {
                 test.actual_screenshot = move(screenshot);
+                view.reset_zoom();
                 view.debug_request("load-reference-page");
             });
         }
@@ -358,6 +367,10 @@ static void run_ref_test(HeadlessWebView& view, Test& test, URL::URL const& url,
         timer->start(milliseconds);
     };
 
+    view.on_set_browser_zoom = [&view](double factor) {
+        view.set_zoom(factor);
+    };
+
     view.load(url);
     timer->start();
 }
diff --git a/UI/Qt/BrowserWindow.h b/UI/Qt/BrowserWindow.h
index 30b418b9961..eafe0ca3cc5 100644
--- a/UI/Qt/BrowserWindow.h
+++ b/UI/Qt/BrowserWindow.h
@@ -133,6 +133,7 @@ public slots:
     void zoom_out();
     void reset_zoom();
     void update_zoom_menu();
+    void update_displayed_zoom_level();
     void select_all();
     void show_find_in_page();
     void paste();
@@ -154,7 +155,6 @@ private:
     void debug_request(ByteString const& request, ByteString const& argument = "");
 
     void set_current_tab(Tab* tab);
-    void update_displayed_zoom_level();
 
     template<typename Callback>
     void for_each_tab(Callback&& callback)
diff --git a/UI/Qt/WebContentView.cpp b/UI/Qt/WebContentView.cpp
index 4d591b6065c..ae98bd594c9 100644
--- a/UI/Qt/WebContentView.cpp
+++ b/UI/Qt/WebContentView.cpp
@@ -164,6 +164,12 @@ WebContentView::WebContentView(QWidget* window, RefPtr<WebView::WebContentClient
 
         m_select_dropdown->exec(map_point_to_global_position(content_position));
     };
+
+    on_set_browser_zoom = [this](double factor) {
+        set_zoom(factor);
+        auto* window = static_cast<BrowserWindow*>(this->window());
+        window->update_displayed_zoom_level();
+    };
 }
 
 WebContentView::~WebContentView() = default;