diff --git a/components/script/dom/formdata.rs b/components/script/dom/formdata.rs
index 003412bb4356..542b44e804eb 100644
--- a/components/script/dom/formdata.rs
+++ b/components/script/dom/formdata.rs
@@ -3,11 +3,12 @@
  * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
 
 use dom::bindings::cell::DOMRefCell;
-use dom::bindings::codegen::Bindings::FormDataBinding;
 use dom::bindings::codegen::Bindings::FormDataBinding::FormDataMethods;
+use dom::bindings::codegen::Bindings::FormDataBinding::FormDataWrap;
 use dom::bindings::codegen::UnionTypes::FileOrUSVString;
 use dom::bindings::error::Fallible;
 use dom::bindings::global::GlobalRef;
+use dom::bindings::iterable::Iterable;
 use dom::bindings::js::Root;
 use dom::bindings::reflector::{Reflectable, Reflector, reflect_dom_object};
 use dom::bindings::str::{DOMString, USVString};
@@ -16,6 +17,7 @@ use dom::file::File;
 use dom::htmlformelement::{HTMLFormElement, FormDatumValue, FormDatum};
 use std::collections::HashMap;
 use std::collections::hash_map::Entry::{Occupied, Vacant};
+use std::iter;
 use string_cache::Atom;
 
 #[dom_struct]
@@ -45,7 +47,7 @@ impl FormData {
 
     pub fn new(form: Option<&HTMLFormElement>, global: GlobalRef) -> Root<FormData> {
         reflect_dom_object(box FormData::new_inherited(form),
-                           global, FormDataBinding::Wrap)
+                           global, FormDataWrap)
     }
 
     pub fn Constructor(global: GlobalRef, form: Option<&HTMLFormElement>) -> Fallible<Root<FormData>> {
@@ -156,11 +158,40 @@ impl FormData {
     }
 
     pub fn datums(&self) -> Vec<FormDatum> {
-        let mut ret = vec![];
-        for values in self.data.borrow().values() {
-            ret.append(&mut values.clone());
+        self.data.borrow().values()
+            .flat_map(|value| value.iter())
+            .map(|value| value.clone())
+            .collect()
+    }
+}
+
+impl Iterable for FormData {
+    type Key = USVString;
+    type Value = FileOrUSVString;
+
+    fn get_iterable_length(&self) -> u32 {
+        self.data.borrow().values().map(|value| value.len()).sum::<usize>() as u32
+    }
+
+    fn get_value_at_index(&self, n: u32) -> FileOrUSVString {
+        let data = self.data.borrow();
+        let value = &data.values()
+                         .flat_map(|value| value.iter())
+                         .nth(n as usize)
+                         .unwrap()
+                         .value;
+        match *value {
+            FormDatumValue::String(ref s) => FileOrUSVString::USVString(USVString(s.to_string())),
+            FormDatumValue::File(ref b) => FileOrUSVString::File(Root::from_ref(&*b)),
         }
+    }
 
-        ret
+    fn get_key_at_index(&self, n: u32) -> USVString {
+        let data = self.data.borrow();
+        let value = &data.iter()
+                         .flat_map(|(key, value)| iter::repeat(key).take(value.len()))
+                         .nth(n as usize)
+                         .unwrap();
+        USVString(value.to_string())
     }
 }
diff --git a/components/script/dom/webidls/FormData.webidl b/components/script/dom/webidls/FormData.webidl
index 0de3ef367609..3c3b3a8d01a2 100644
--- a/components/script/dom/webidls/FormData.webidl
+++ b/components/script/dom/webidls/FormData.webidl
@@ -19,5 +19,5 @@ interface FormData {
   boolean has(USVString name);
   void set(USVString name, USVString value);
   void set(USVString name, Blob value, optional USVString filename);
-  // iterable<USVString, FormDataEntryValue>;
+  iterable<USVString, FormDataEntryValue>;
 };
diff --git a/tests/wpt/metadata/MANIFEST.json b/tests/wpt/metadata/MANIFEST.json
index 4dd9d658d0a6..058ec3eac5eb 100644
--- a/tests/wpt/metadata/MANIFEST.json
+++ b/tests/wpt/metadata/MANIFEST.json
@@ -12837,6 +12837,10 @@
         "path": "XMLHttpRequest/formdata-delete.htm",
         "url": "/XMLHttpRequest/formdata-delete.htm"
       },
+      {
+        "path": "XMLHttpRequest/formdata-foreach.html",
+        "url": "/XMLHttpRequest/formdata-foreach.html"
+      },
       {
         "path": "XMLHttpRequest/formdata-get.htm",
         "url": "/XMLHttpRequest/formdata-get.htm"
diff --git a/tests/wpt/metadata/XMLHttpRequest/formdata-foreach.html.ini b/tests/wpt/metadata/XMLHttpRequest/formdata-foreach.html.ini
new file mode 100644
index 000000000000..2de0609bfc2d
--- /dev/null
+++ b/tests/wpt/metadata/XMLHttpRequest/formdata-foreach.html.ini
@@ -0,0 +1,13 @@
+[formdata-foreach.html]
+  type: testharness
+  [Iterator should return duplicate keys and non-deleted values]
+    expected: FAIL
+
+  [Entries iterator should return duplicate keys and non-deleted values]
+    expected: FAIL
+
+  [Keys iterator should return duplicates]
+    expected: FAIL
+
+  [Values iterator should return non-deleted values]
+    expected: FAIL
diff --git a/tests/wpt/web-platform-tests/XMLHttpRequest/formdata-foreach.html b/tests/wpt/web-platform-tests/XMLHttpRequest/formdata-foreach.html
new file mode 100644
index 000000000000..9b10367aece1
--- /dev/null
+++ b/tests/wpt/web-platform-tests/XMLHttpRequest/formdata-foreach.html
@@ -0,0 +1,59 @@
+<!doctype html>
+<html lang=en>
+<meta charset=utf-8>
+<title>FormData: foreach</title>
+<script src="/resources/testharness.js"></script>
+<script src="/resources/testharnessreport.js"></script>
+    <link rel="help" href="https://xhr.spec.whatwg.org/#interface-formdata" />
+<script>
+    var fd = new FormData();
+    fd.append('n1', 'v1');
+    fd.append('n2', 'v2');
+    fd.append('n3', 'v3');
+    fd.append('n1', 'v4');
+    fd.append('n2', 'v5');
+    fd.append('n3', 'v6');
+    fd.delete('n2');
+    var expected_keys = ['n1', 'n3', 'n1', 'n3'];
+    var expected_values = ['v1', 'v3', 'v4', 'v6'];
+    test(function() {
+        var mykeys = [], myvalues = [];
+        for(var entry of fd) {
+            assert_equals(entry.length, 2,
+                          'Default iterator should yield key/value pairs');
+            mykeys.push(entry[0]);
+            myvalues.push(entry[1]);
+        }
+        assert_array_equals(mykeys, expected_keys,
+                            'Default iterator should see duplicate keys');
+        assert_array_equals(myvalues, expected_values,
+                            'Default iterator should see non-deleted values');
+    }, 'Iterator should return duplicate keys and non-deleted values');
+    test(function() {
+        var mykeys = [], myvalues = [];
+        for(var entry of fd.entries()) {
+            assert_equals(entry.length, 2,
+                          'entries() iterator should yield key/value pairs');
+            mykeys.push(entry[0]);
+            myvalues.push(entry[1]);
+        }
+        assert_array_equals(mykeys, expected_keys,
+                            'entries() iterator should see duplicate keys');
+        assert_array_equals(myvalues, expected_values,
+                            'entries() iterator should see non-deleted values');
+    }, 'Entries iterator should return duplicate keys and non-deleted values');
+    test(function() {
+        var mykeys = [];
+        for(var entry of fd.keys())
+            mykeys.push(entry);
+        assert_array_equals(mykeys, expected_keys,
+                            'keys() iterator should see duplicate keys');
+    }, 'Keys iterator should return duplicates');
+    test(function() {
+        var myvalues = [];
+        for(var entry of fd.values())
+            myvalues.push(entry);
+        assert_array_equals(myvalues, expected_values,
+                            'values() iterator should see non-deleted values');
+    }, 'Values iterator should return non-deleted values');
+</script>