diff --git a/Userland/Libraries/LibWeb/DOM/Node.h b/Userland/Libraries/LibWeb/DOM/Node.h
index 5bd932328f..f1be385128 100644
--- a/Userland/Libraries/LibWeb/DOM/Node.h
+++ b/Userland/Libraries/LibWeb/DOM/Node.h
@@ -103,6 +103,7 @@ public:
     virtual bool is_html_table_cell_element() const { return false; }
     virtual bool is_html_br_element() const { return false; }
     virtual bool is_html_button_element() const { return false; }
+    virtual bool is_html_slot_element() const { return false; }
     virtual bool is_navigable_container() const { return false; }
 
     WebIDL::ExceptionOr<JS::NonnullGCPtr<Node>> pre_insert(JS::NonnullGCPtr<Node>, JS::GCPtr<Node>);
diff --git a/Userland/Libraries/LibWeb/HTML/HTMLSlotElement.h b/Userland/Libraries/LibWeb/HTML/HTMLSlotElement.h
index cef72057ff..d468c86a67 100644
--- a/Userland/Libraries/LibWeb/HTML/HTMLSlotElement.h
+++ b/Userland/Libraries/LibWeb/HTML/HTMLSlotElement.h
@@ -39,6 +39,8 @@ public:
 private:
     HTMLSlotElement(DOM::Document&, DOM::QualifiedName);
 
+    virtual bool is_html_slot_element() const override { return true; }
+
     virtual void initialize(JS::Realm&) override;
     virtual void visit_edges(JS::Cell::Visitor&) override;
 
@@ -47,3 +49,10 @@ private:
 };
 
 }
+
+namespace Web::DOM {
+
+template<>
+inline bool Node::fast_is<HTML::HTMLSlotElement>() const { return is_html_slot_element(); }
+
+}