diff --git a/Userland/Libraries/LibWeb/HTML/HTMLSlotElement.cpp b/Userland/Libraries/LibWeb/HTML/HTMLSlotElement.cpp
index 90791644710..e3a7d5b0885 100644
--- a/Userland/Libraries/LibWeb/HTML/HTMLSlotElement.cpp
+++ b/Userland/Libraries/LibWeb/HTML/HTMLSlotElement.cpp
@@ -38,7 +38,7 @@ void HTMLSlotElement::visit_edges(JS::Cell::Visitor& visitor)
 }
 
 // https://html.spec.whatwg.org/multipage/scripting.html#dom-slot-assignednodes
-Vector<JS::Handle<DOM::Node>> HTMLSlotElement::assigned_nodes(AssignedNodesOptions options)
+Vector<JS::Handle<DOM::Node>> HTMLSlotElement::assigned_nodes(AssignedNodesOptions options) const
 {
     // 1. If options["flatten"] is false, then return this's assigned nodes.
     if (!options.flatten) {
@@ -59,7 +59,7 @@ Vector<JS::Handle<DOM::Node>> HTMLSlotElement::assigned_nodes(AssignedNodesOptio
 }
 
 // https://html.spec.whatwg.org/multipage/scripting.html#dom-slot-assignedelements
-Vector<JS::Handle<DOM::Element>> HTMLSlotElement::assigned_elements(AssignedNodesOptions options)
+Vector<JS::Handle<DOM::Element>> HTMLSlotElement::assigned_elements(AssignedNodesOptions options) const
 {
     // 1. If options["flatten"] is false, then return this's assigned nodes, filtered to contain only Element nodes.
     if (!options.flatten) {
diff --git a/Userland/Libraries/LibWeb/HTML/HTMLSlotElement.h b/Userland/Libraries/LibWeb/HTML/HTMLSlotElement.h
index 2ab591bc5db..3b579264048 100644
--- a/Userland/Libraries/LibWeb/HTML/HTMLSlotElement.h
+++ b/Userland/Libraries/LibWeb/HTML/HTMLSlotElement.h
@@ -29,8 +29,8 @@ class HTMLSlotElement final
 public:
     virtual ~HTMLSlotElement() override;
 
-    Vector<JS::Handle<DOM::Node>> assigned_nodes(AssignedNodesOptions options = {});
-    Vector<JS::Handle<DOM::Element>> assigned_elements(AssignedNodesOptions options = {});
+    Vector<JS::Handle<DOM::Node>> assigned_nodes(AssignedNodesOptions options = {}) const;
+    Vector<JS::Handle<DOM::Element>> assigned_elements(AssignedNodesOptions options = {}) const;
 
     using SlottableHandle = Variant<JS::Handle<DOM::Element>, JS::Handle<DOM::Text>>;
     void assign(Vector<SlottableHandle> nodes);