diff --git a/components/script/dom/htmldialogelement.rs b/components/script/dom/htmldialogelement.rs
index 621eefcd8a4..1afd7f0d76f 100644
--- a/components/script/dom/htmldialogelement.rs
+++ b/components/script/dom/htmldialogelement.rs
@@ -5,11 +5,14 @@
 use dom::bindings::cell::DOMRefCell;
 use dom::bindings::codegen::Bindings::HTMLDialogElementBinding;
 use dom::bindings::codegen::Bindings::HTMLDialogElementBinding::HTMLDialogElementMethods;
+use dom::bindings::inheritance::Castable;
 use dom::bindings::js::Root;
 use dom::bindings::str::DOMString;
 use dom::document::Document;
+use dom::element::Element;
+use dom::eventtarget::EventTarget;
 use dom::htmlelement::HTMLElement;
-use dom::node::Node;
+use dom::node::{Node, window_from_node};
 use string_cache::Atom;
 
 #[dom_struct]
@@ -56,4 +59,26 @@ impl HTMLDialogElementMethods for HTMLDialogElement {
     fn SetReturnValue(&self, return_value: DOMString) {
         *self.return_value.borrow_mut() = return_value;
     }
+
+    // https://html.spec.whatwg.org/multipage/#dom-dialog-close
+    fn Close(&self, return_value: Option<DOMString>) {
+        let element = self.upcast::<Element>();
+        let target = self.upcast::<EventTarget>();
+        let win = window_from_node(self);
+
+        // Step 1 & 2
+        if element.remove_attribute(&ns!(), &atom!("open")).is_none() {
+            return;
+        }
+
+        // Step 3
+        if let Some(new_value) = return_value {
+            *self.return_value.borrow_mut() = new_value;
+        }
+
+        // TODO: Step 4 implement pending dialog stack removal
+
+        // Step 5
+        win.dom_manipulation_task_source().queue_simple_event(target, atom!("close"), win.r());
+    }
 }
diff --git a/components/script/dom/webidls/HTMLDialogElement.webidl b/components/script/dom/webidls/HTMLDialogElement.webidl
index 78a14e1e2a0..0ac76a0465e 100644
--- a/components/script/dom/webidls/HTMLDialogElement.webidl
+++ b/components/script/dom/webidls/HTMLDialogElement.webidl
@@ -8,5 +8,5 @@ interface HTMLDialogElement : HTMLElement {
   attribute DOMString returnValue;
   //void show(optional (MouseEvent or Element) anchor);
   //void showModal(optional (MouseEvent or Element) anchor);
-  //void close(optional DOMString returnValue);
+  void close(optional DOMString returnValue);
 };
diff --git a/tests/wpt/metadata/html/dom/interfaces.html.ini b/tests/wpt/metadata/html/dom/interfaces.html.ini
index c444dcc4a8a..f767443f366 100644
--- a/tests/wpt/metadata/html/dom/interfaces.html.ini
+++ b/tests/wpt/metadata/html/dom/interfaces.html.ini
@@ -4374,9 +4374,6 @@
   [HTMLDialogElement interface: operation showModal([object Object\],[object Object\])]
     expected: FAIL
 
-  [HTMLDialogElement interface: operation close(DOMString)]
-    expected: FAIL
-
   [HTMLScriptElement interface: attribute async]
     expected: FAIL
 
diff --git a/tests/wpt/metadata/html/semantics/interactive-elements/the-dialog-element/dialog-close.html.ini b/tests/wpt/metadata/html/semantics/interactive-elements/the-dialog-element/dialog-close.html.ini
index f3efb4a6ccf..436d9b2601c 100644
--- a/tests/wpt/metadata/html/semantics/interactive-elements/the-dialog-element/dialog-close.html.ini
+++ b/tests/wpt/metadata/html/semantics/interactive-elements/the-dialog-element/dialog-close.html.ini
@@ -1,17 +1,5 @@
 [dialog-close.html]
   type: testharness
-  [close() fires a close event]
-    expected: FAIL
-
   [close() on a <dialog> that doesn't have an open attribute throws an InvalidStateError exception]
     expected: FAIL
 
-  [close() removes the open attribute and set the returnValue to the first argument]
-    expected: FAIL
-
-  [close() without argument removes the open attribute and there's no returnValue]
-    expected: FAIL
-
-  [close() should set the returnValue IDL attribute but not the JS property]
-    expected: FAIL
-
diff --git a/tests/wpt/web-platform-tests/html/semantics/interactive-elements/the-dialog-element/dialog-close.html b/tests/wpt/web-platform-tests/html/semantics/interactive-elements/the-dialog-element/dialog-close.html
index a3d07f053dc..9029612b241 100644
--- a/tests/wpt/web-platform-tests/html/semantics/interactive-elements/the-dialog-element/dialog-close.html
+++ b/tests/wpt/web-platform-tests/html/semantics/interactive-elements/the-dialog-element/dialog-close.html
@@ -36,10 +36,9 @@
       was_queued = false;
 
   test(function(){
-    assert_throws("INVALID_STATE_ERR", function() {
-      d1.close();
-    });
-  }, "close() on a <dialog> that doesn't have an open attribute throws an InvalidStateError exception");
+    d1.close("closedialog");
+    assert_equals(d1.returnValue, "");
+  }, "close() on a <dialog> that doesn't have an open attribute aborts the steps");
 
   test(function(){
     assert_true(d2.open);