diff --git a/components/script/dom/element.rs b/components/script/dom/element.rs
index 98c0a8eb799..3ddf6b4f769 100644
--- a/components/script/dom/element.rs
+++ b/components/script/dom/element.rs
@@ -1228,6 +1228,11 @@ impl ElementMethods for Element {
         self.attr_list.or_init(|| NamedNodeMap::new(&window_from_node(self), self))
     }
 
+    // https://dom.spec.whatwg.org/#dom-element-getattributenames
+    fn GetAttributeNames(&self) -> Vec<DOMString> {
+        self.attrs.borrow().iter().map(|attr| attr.Name()).collect()
+    }
+
     // https://dom.spec.whatwg.org/#dom-element-getattribute
     fn GetAttribute(&self, name: DOMString) -> Option<DOMString> {
         self.GetAttributeNode(name)
diff --git a/components/script/dom/webidls/Element.webidl b/components/script/dom/webidls/Element.webidl
index 1a9b74bb9f2..21c9f8234f0 100644
--- a/components/script/dom/webidls/Element.webidl
+++ b/components/script/dom/webidls/Element.webidl
@@ -34,6 +34,8 @@ interface Element : Node {
   [SameObject]
   readonly attribute NamedNodeMap attributes;
   [Pure]
+  sequence<DOMString> getAttributeNames();
+  [Pure]
   DOMString? getAttribute(DOMString name);
   [Pure]
   DOMString? getAttributeNS(DOMString? namespace, DOMString localName);
diff --git a/tests/wpt/metadata/dom/interfaces.html.ini b/tests/wpt/metadata/dom/interfaces.html.ini
index f45ecd075a1..65c1d82f2cf 100644
--- a/tests/wpt/metadata/dom/interfaces.html.ini
+++ b/tests/wpt/metadata/dom/interfaces.html.ini
@@ -120,19 +120,19 @@
   [Element interface: element must inherit property "hasAttributes" with the proper type (7)]
     expected: FAIL
 
-  [Element interface: element must inherit property "removeAttributeNode" with the proper type (21)]
+  [Element interface: element must inherit property "removeAttributeNode" with the proper type (22)]
     expected: FAIL
 
   [Element interface: calling removeAttributeNode(Attr) on element with too few arguments must throw TypeError]
     expected: FAIL
 
-  [Element interface: element must inherit property "query" with the proper type (33)]
+  [Element interface: element must inherit property "query" with the proper type (34)]
     expected: FAIL
 
   [Element interface: calling query(DOMString) on element with too few arguments must throw TypeError]
     expected: FAIL
 
-  [Element interface: element must inherit property "queryAll" with the proper type (34)]
+  [Element interface: element must inherit property "queryAll" with the proper type (35)]
     expected: FAIL
 
   [Element interface: calling queryAll(DOMString) on element with too few arguments must throw TypeError]
diff --git a/tests/wpt/metadata/dom/nodes/attributes.html.ini b/tests/wpt/metadata/dom/nodes/attributes.html.ini
index c66885207f2..1531de6e1a8 100644
--- a/tests/wpt/metadata/dom/nodes/attributes.html.ini
+++ b/tests/wpt/metadata/dom/nodes/attributes.html.ini
@@ -3,9 +3,6 @@
   [Basic functionality of removeAttributeNode]
     expected: FAIL
 
-  [getAttributeNames tests]
-    expected: FAIL
-
   [Own property names should only include all-lowercase qualified names for an HTML element in an HTML document]
     expected: FAIL
 
diff --git a/tests/wpt/metadata/html/dom/interfaces.html.ini b/tests/wpt/metadata/html/dom/interfaces.html.ini
index 784d086c1a2..7e7c9590db6 100644
--- a/tests/wpt/metadata/html/dom/interfaces.html.ini
+++ b/tests/wpt/metadata/html/dom/interfaces.html.ini
@@ -1986,19 +1986,19 @@
   [Element interface: document.createElement("noscript") must inherit property "hasAttributes" with the proper type (7)]
     expected: FAIL
 
-  [Element interface: document.createElement("noscript") must inherit property "removeAttributeNode" with the proper type (21)]
+  [Element interface: document.createElement("noscript") must inherit property "removeAttributeNode" with the proper type (22)]
     expected: FAIL
 
   [Element interface: calling removeAttributeNode(Attr) on document.createElement("noscript") with too few arguments must throw TypeError]
     expected: FAIL
 
-  [Element interface: document.createElement("noscript") must inherit property "query" with the proper type (33)]
+  [Element interface: document.createElement("noscript") must inherit property "query" with the proper type (34)]
     expected: FAIL
 
   [Element interface: calling query(DOMString) on document.createElement("noscript") with too few arguments must throw TypeError]
     expected: FAIL
 
-  [Element interface: document.createElement("noscript") must inherit property "queryAll" with the proper type (34)]
+  [Element interface: document.createElement("noscript") must inherit property "queryAll" with the proper type (35)]
     expected: FAIL
 
   [Element interface: calling queryAll(DOMString) on document.createElement("noscript") with too few arguments must throw TypeError]
diff --git a/tests/wpt/web-platform-tests/dom/interfaces.html b/tests/wpt/web-platform-tests/dom/interfaces.html
index 00cf70eb92d..591c5ab3c98 100644
--- a/tests/wpt/web-platform-tests/dom/interfaces.html
+++ b/tests/wpt/web-platform-tests/dom/interfaces.html
@@ -287,6 +287,7 @@ interface Element : Node {
 
   boolean hasAttributes();
   [SameObject] readonly attribute NamedNodeMap attributes;
+  sequence<DOMString> getAttributeNames();
   DOMString? getAttribute(DOMString name);
   DOMString? getAttributeNS(DOMString? namespace, DOMString localName);
   void setAttribute(DOMString name, DOMString value);
diff --git a/tests/wpt/web-platform-tests/html/dom/interfaces.html b/tests/wpt/web-platform-tests/html/dom/interfaces.html
index a9991a1f28e..8067495623f 100644
--- a/tests/wpt/web-platform-tests/html/dom/interfaces.html
+++ b/tests/wpt/web-platform-tests/html/dom/interfaces.html
@@ -289,6 +289,7 @@ interface Element : Node {
 
   boolean hasAttributes();
   [SameObject] readonly attribute NamedNodeMap attributes;
+  sequence<DOMString> getAttributeNames();
   DOMString? getAttribute(DOMString name);
   DOMString? getAttributeNS(DOMString? namespace, DOMString localName);
   void setAttribute(DOMString name, DOMString value);