diff --git a/Userland/Libraries/LibWeb/DOM/Document.idl b/Userland/Libraries/LibWeb/DOM/Document.idl
index 173b73cca7..275a75941f 100644
--- a/Userland/Libraries/LibWeb/DOM/Document.idl
+++ b/Userland/Libraries/LibWeb/DOM/Document.idl
@@ -67,6 +67,7 @@ interface Document : Node {
 
     [CEReactions, Unscopable] undefined prepend((Node or DOMString)... nodes);
     [CEReactions, Unscopable] undefined append((Node or DOMString)... nodes);
+    [CEReactions, Unscopable] undefined replaceChildren((Node or DOMString)... nodes);
 
     Element? querySelector(DOMString selectors);
     [NewObject] NodeList querySelectorAll(DOMString selectors);
diff --git a/Userland/Libraries/LibWeb/DOM/DocumentFragment.idl b/Userland/Libraries/LibWeb/DOM/DocumentFragment.idl
index 5309a72957..2735e9c70c 100644
--- a/Userland/Libraries/LibWeb/DOM/DocumentFragment.idl
+++ b/Userland/Libraries/LibWeb/DOM/DocumentFragment.idl
@@ -11,6 +11,7 @@ interface DocumentFragment : Node {
 
     [CEReactions, Unscopable] undefined prepend((Node or DOMString)... nodes);
     [CEReactions, Unscopable] undefined append((Node or DOMString)... nodes);
+    [CEReactions, Unscopable] undefined replaceChildren((Node or DOMString)... nodes);
 
     Element? querySelector(DOMString selectors);
     [NewObject] NodeList querySelectorAll(DOMString selectors);
diff --git a/Userland/Libraries/LibWeb/DOM/Element.idl b/Userland/Libraries/LibWeb/DOM/Element.idl
index 66da1ec84f..41d664994d 100644
--- a/Userland/Libraries/LibWeb/DOM/Element.idl
+++ b/Userland/Libraries/LibWeb/DOM/Element.idl
@@ -40,6 +40,7 @@ interface Element : Node {
 
     [CEReactions, Unscopable] undefined prepend((Node or DOMString)... nodes);
     [CEReactions, Unscopable] undefined append((Node or DOMString)... nodes);
+    [CEReactions, Unscopable] undefined replaceChildren((Node or DOMString)... nodes);
 
     Element? querySelector(DOMString selectors);
     [NewObject] NodeList querySelectorAll(DOMString selectors);
diff --git a/Userland/Libraries/LibWeb/DOM/ParentNode.cpp b/Userland/Libraries/LibWeb/DOM/ParentNode.cpp
index b2587bb396..dde6fc9b43 100644
--- a/Userland/Libraries/LibWeb/DOM/ParentNode.cpp
+++ b/Userland/Libraries/LibWeb/DOM/ParentNode.cpp
@@ -191,4 +191,23 @@ ExceptionOr<void> ParentNode::append(Vector<Variant<NonnullRefPtr<Node>, String>
     return {};
 }
 
+ExceptionOr<void> ParentNode::replace_children(Vector<Variant<NonnullRefPtr<Node>, String>> const& nodes)
+{
+    // 1. Let node be the result of converting nodes into a node given nodes and this’s node document.
+    auto node_or_exception = convert_nodes_to_single_node(nodes, document());
+    if (node_or_exception.is_exception())
+        return node_or_exception.exception();
+
+    auto node = node_or_exception.release_value();
+
+    // 2. Ensure pre-insertion validity of node into this before null.
+    auto validity_exception = ensure_pre_insertion_validity(node, nullptr);
+    if (validity_exception.is_exception())
+        return validity_exception.exception();
+
+    // 3. Replace all with node within this.
+    replace_all(node);
+    return {};
+}
+
 }
diff --git a/Userland/Libraries/LibWeb/DOM/ParentNode.h b/Userland/Libraries/LibWeb/DOM/ParentNode.h
index e3ee6abf08..1b8c3e3c5c 100644
--- a/Userland/Libraries/LibWeb/DOM/ParentNode.h
+++ b/Userland/Libraries/LibWeb/DOM/ParentNode.h
@@ -32,6 +32,7 @@ public:
 
     ExceptionOr<void> prepend(Vector<Variant<NonnullRefPtr<Node>, String>> const& nodes);
     ExceptionOr<void> append(Vector<Variant<NonnullRefPtr<Node>, String>> const& nodes);
+    ExceptionOr<void> replace_children(Vector<Variant<NonnullRefPtr<Node>, String>> const& nodes);
 
 protected:
     ParentNode(Document& document, NodeType type)