diff --git a/Userland/Libraries/LibWeb/Bindings/WindowObject.cpp b/Userland/Libraries/LibWeb/Bindings/WindowObject.cpp
index 1a7bfb2719..81f1a36d3a 100644
--- a/Userland/Libraries/LibWeb/Bindings/WindowObject.cpp
+++ b/Userland/Libraries/LibWeb/Bindings/WindowObject.cpp
@@ -67,6 +67,8 @@ void WindowObject::initialize()
     define_property("self", this, JS::Attribute::Enumerable);
     define_native_property("document", document_getter, document_setter, JS::Attribute::Enumerable);
     define_native_property("performance", performance_getter, nullptr, JS::Attribute::Enumerable);
+    define_native_property("innerWidth", inner_width_getter, nullptr, JS::Attribute::Enumerable);
+    define_native_property("innerHeight", inner_height_getter, nullptr, JS::Attribute::Enumerable);
     define_native_function("alert", alert);
     define_native_function("confirm", confirm);
     define_native_function("prompt", prompt);
@@ -379,4 +381,20 @@ JS_DEFINE_NATIVE_GETTER(WindowObject::event_getter)
     return wrap(global_object, const_cast<DOM::Event&>(*impl->current_event()));
 }
 
+JS_DEFINE_NATIVE_GETTER(WindowObject::inner_width_getter)
+{
+    auto* impl = impl_from(vm, global_object);
+    if (!impl)
+        return {};
+    return JS::Value(impl->inner_width());
+}
+
+JS_DEFINE_NATIVE_GETTER(WindowObject::inner_height_getter)
+{
+    auto* impl = impl_from(vm, global_object);
+    if (!impl)
+        return {};
+    return JS::Value(impl->inner_height());
+}
+
 }
diff --git a/Userland/Libraries/LibWeb/Bindings/WindowObject.h b/Userland/Libraries/LibWeb/Bindings/WindowObject.h
index 48d95212c7..097237bf03 100644
--- a/Userland/Libraries/LibWeb/Bindings/WindowObject.h
+++ b/Userland/Libraries/LibWeb/Bindings/WindowObject.h
@@ -84,6 +84,9 @@ private:
 
     JS_DECLARE_NATIVE_GETTER(event_getter);
 
+    JS_DECLARE_NATIVE_GETTER(inner_width_getter);
+    JS_DECLARE_NATIVE_GETTER(inner_height_getter);
+
     JS_DECLARE_NATIVE_FUNCTION(alert);
     JS_DECLARE_NATIVE_FUNCTION(confirm);
     JS_DECLARE_NATIVE_FUNCTION(prompt);
diff --git a/Userland/Libraries/LibWeb/DOM/Window.cpp b/Userland/Libraries/LibWeb/DOM/Window.cpp
index 0b7f66afc4..62c327fd75 100644
--- a/Userland/Libraries/LibWeb/DOM/Window.cpp
+++ b/Userland/Libraries/LibWeb/DOM/Window.cpp
@@ -33,6 +33,7 @@
 #include <LibWeb/DOM/Window.h>
 #include <LibWeb/HighResolutionTime/Performance.h>
 #include <LibWeb/InProcessWebView.h>
+#include <LibWeb/Layout/InitialContainingBlockBox.h>
 #include <LibWeb/Page/Frame.h>
 
 namespace Web::DOM {
@@ -181,4 +182,18 @@ JS::Object* Window::create_wrapper(JS::GlobalObject& global_object)
     return &global_object;
 }
 
+int Window::inner_width() const
+{
+    if (!document().layout_node())
+        return 0;
+    return document().layout_node()->width();
+}
+
+int Window::inner_height() const
+{
+    if (!document().layout_node())
+        return 0;
+    return document().layout_node()->height();
+}
+
 }
diff --git a/Userland/Libraries/LibWeb/DOM/Window.h b/Userland/Libraries/LibWeb/DOM/Window.h
index 4227130eec..25d7138438 100644
--- a/Userland/Libraries/LibWeb/DOM/Window.h
+++ b/Userland/Libraries/LibWeb/DOM/Window.h
@@ -66,6 +66,9 @@ public:
     void clear_timeout(i32);
     void clear_interval(i32);
 
+    int inner_width() const;
+    int inner_height() const;
+
     void did_set_location_href(Badge<Bindings::LocationObject>, const URL& new_href);
     void did_call_location_reload(Badge<Bindings::LocationObject>);