diff --git a/src/components/script/dom/bindings/codegen/Bindings.conf b/src/components/script/dom/bindings/codegen/Bindings.conf
index ffa19b30198..7cff64d5ade 100644
--- a/src/components/script/dom/bindings/codegen/Bindings.conf
+++ b/src/components/script/dom/bindings/codegen/Bindings.conf
@@ -32,6 +32,7 @@ DOMInterfaces = {
         'createElement',
         'createProcessingInstruction',
         'createTextNode',
+        'getElementsByClassName',
         'getElementsByTagName',
         'getElementsByTagNameNS',
         'title',
@@ -45,6 +46,7 @@ DOMInterfaces = {
         'attributes',
         'getBoundingClientRect',
         'getClientRects',
+        'getElementsByClassName',
         'getElementsByTagName',
         'getElementsByTagNameNS',
         'id',
diff --git a/src/components/script/dom/document.rs b/src/components/script/dom/document.rs
index fba0d4b506f..95de6ab2fac 100644
--- a/src/components/script/dom/document.rs
+++ b/src/components/script/dom/document.rs
@@ -225,6 +225,11 @@ impl Document {
         HTMLCollection::by_tag_name_ns(&self.window, &NodeCast::from(abstract_self), tag_name, namespace)
     }
 
+    // http://dom.spec.whatwg.org/#dom-document-getelementsbyclassname
+    pub fn GetElementsByClassName(&self, abstract_self: &JS<Document>, classes: DOMString) -> JS<HTMLCollection> {
+        HTMLCollection::by_class_name(&self.window, &NodeCast::from(abstract_self), classes)
+    }
+
     // http://dom.spec.whatwg.org/#dom-nonelementparentnode-getelementbyid
     pub fn GetElementById(&self, id: DOMString) -> Option<JS<Element>> {
         // TODO: "in tree order, within the context object's tree"
diff --git a/src/components/script/dom/element.rs b/src/components/script/dom/element.rs
index a004126cc6d..95e4e7f9af9 100644
--- a/src/components/script/dom/element.rs
+++ b/src/components/script/dom/element.rs
@@ -370,6 +370,13 @@ impl Element {
             _ => false
         }
     }
+
+    pub fn has_class(&self, name: &str) -> bool {
+        // FIXME: https://github.com/mozilla/servo/issues/1840
+        let class_names = self.get_string_attribute("class");
+        let mut classes = class_names.split(' ');
+        classes.any(|class| name == class)
+    }
 }
 
 // http://www.whatwg.org/html/#reflecting-content-attributes-in-idl-attributes
@@ -520,11 +527,10 @@ impl Element {
         HTMLCollection::by_tag_name_ns(&doc.window, &NodeCast::from(abstract_self), localname, namespace)
     }
 
-    // http://dom.spec.whatwg.org/#dom-element-getelementsbyclassname
-    pub fn GetElementsByClassName(&self, _names: DOMString) -> JS<HTMLCollection> {
-        // FIXME: stub - https://github.com/mozilla/servo/issues/1660
+    pub fn GetElementsByClassName(&self, abstract_self: &JS<Element>, classes: DOMString) -> JS<HTMLCollection> {
         let doc = self.node.owner_doc();
-        HTMLCollection::new(&doc.get().window, ~[])
+        let doc = doc.get();
+        HTMLCollection::by_class_name(&doc.window, &NodeCast::from(abstract_self), classes)
     }
 
     // http://dev.w3.org/csswg/cssom-view/#dom-element-getclientrects
diff --git a/src/components/script/dom/htmlcollection.rs b/src/components/script/dom/htmlcollection.rs
index 4d18e9734f4..96e04d46d3b 100644
--- a/src/components/script/dom/htmlcollection.rs
+++ b/src/components/script/dom/htmlcollection.rs
@@ -55,6 +55,12 @@ impl HTMLCollection {
     pub fn by_tag_name_ns(window: &JS<Window>, root: &JS<Node>, tag_name: DOMString, namespace: Namespace) -> JS<HTMLCollection> {
         HTMLCollection::create(window, root, |elem| elem.get().namespace == namespace && elem.get().tag_name == tag_name)
     }
+
+    pub fn by_class_name(window: &JS<Window>, root: &JS<Node>, classes: DOMString) -> JS<HTMLCollection> {
+        // FIXME: https://github.com/mozilla/servo/issues/1840
+        let classes: ~[&str] = classes.split(' ').collect();
+        HTMLCollection::create(window, root, |elem| classes.iter().all(|class| elem.get().has_class(*class)))
+    }
 }
 
 impl HTMLCollection {
diff --git a/src/components/script/dom/webidls/Document.webidl b/src/components/script/dom/webidls/Document.webidl
index 9dc92b1520f..98df0b2aef9 100644
--- a/src/components/script/dom/webidls/Document.webidl
+++ b/src/components/script/dom/webidls/Document.webidl
@@ -22,6 +22,7 @@ interface Document : Node {
   readonly attribute Element? documentElement;
   HTMLCollection getElementsByTagName(DOMString localName);
   HTMLCollection getElementsByTagNameNS(DOMString? namespace, DOMString localName);
+  HTMLCollection getElementsByClassName(DOMString classNames);
   Element? getElementById(DOMString elementId);
 
   [Creator, Throws]