diff --git a/src/3p-frame.js b/src/3p-frame.js
index 2a5e06b540b0..51ab5b3c9f69 100644
--- a/src/3p-frame.js
+++ b/src/3p-frame.js
@@ -30,7 +30,7 @@ import {viewerFor} from './viewer';
 
 
 /** @type {!Object<string,number>} Number of 3p frames on the for that type. */
-const count = {};
+let count = {};
 
 
 /**
@@ -103,13 +103,15 @@ export function getIframe(parentWindow, element, opt_type) {
   if (!count[attributes.type]) {
     count[attributes.type] = 0;
   }
-  iframe.name = 'frame_' + attributes.type + '_' + count[attributes.type]++;
 
+  const baseUrl = getBootstrapBaseUrl(parentWindow);
+  const host = parseUrl(baseUrl).hostname;
   // Pass ad attributes to iframe via the fragment.
-  const src = getBootstrapBaseUrl(parentWindow) + '#' +
-      JSON.stringify(attributes);
+  const src = baseUrl + '#' + JSON.stringify(attributes);
+  const name = host + '_' + attributes.type + '_' + count[attributes.type]++;
 
   iframe.src = src;
+  iframe.name = name;
   iframe.ampLocation = parseUrl(src);
   iframe.width = attributes.width;
   iframe.height = attributes.height;
@@ -190,17 +192,15 @@ export function getBootstrapBaseUrl(parentWindow, opt_strictForUnitTest) {
  * @return {string}
  */
 function getDefaultBootstrapBaseUrl(parentWindow) {
-  let url =
-      'https://' + getSubDomain(parentWindow) +
-      '.ampproject.net/$internalRuntimeVersion$/frame.html';
   if (getMode().localDev) {
-    url = 'http://ads.localhost:' +
+    return 'http://ads.localhost:' +
         (parentWindow.location.port || parentWindow.parent.location.port) +
         '/dist.3p/current' +
         (getMode().minified ? '-min/frame' : '/frame.max') +
         '.html';
   }
-  return url;
+  return 'https://' + getSubDomain(parentWindow) +
+      '.ampproject.net/$internalRuntimeVersion$/frame.html';
 }
 
 /**
@@ -250,6 +250,14 @@ function getCustomBootstrapBaseUrl(parentWindow, opt_strictForUnitTest) {
       '3p iframe url must not be on the same origin as the current doc' +
       'ument %s (%s) in element %s. See https://github.com/ampproject/amphtml' +
       '/blob/master/spec/amp-iframe-origin-policy.md for details.', url,
-      parseUrl(url).origin, meta);
+      parsed.origin, meta);
   return url + '?$internalRuntimeVersion$';
 }
+
+/**
+ * Resets the count of each 3p frame type
+ * @visibleForTesting
+ */
+export function resetCountForTesting() {
+  count = {};
+}
diff --git a/test/functional/test-3p-frame.js b/test/functional/test-3p-frame.js
index 1e2ef60a20f7..575508fed729 100644
--- a/test/functional/test-3p-frame.js
+++ b/test/functional/test-3p-frame.js
@@ -14,8 +14,14 @@
  * limitations under the License.
  */
 
-import {addDataAndJsonAttributes_, getIframe, getBootstrapBaseUrl,
-    getSubDomain, prefetchBootstrap} from '../../src/3p-frame';
+import {
+  addDataAndJsonAttributes_,
+  getIframe,
+  getBootstrapBaseUrl,
+  getSubDomain,
+  prefetchBootstrap,
+  resetCountForTesting,
+} from '../../src/3p-frame';
 import {validateData} from '../../src/3p';
 import {documentInfoFor} from '../../src/document-info';
 import {loadPromise} from '../../src/event-helper';
@@ -36,6 +42,7 @@ describe('3p-frame', () => {
   afterEach(() => {
     sandbox.restore();
     resetServiceForTesting(window, 'bootstrapBaseUrl');
+    resetCountForTesting();
     setModeForTesting(null);
     const m = document.querySelector(
         '[name="amp-3p-iframe-src"]');
@@ -238,4 +245,33 @@ describe('3p-frame', () => {
     };
     expect(getSubDomain(fakeWin)).to.equal('d-5670');
   });
+
+  it('uses a unique name based on domain', () => {
+    const viewerMock = sandbox.mock(viewerFor(window));
+    viewerMock.expects('getUnconfirmedReferrerUrl')
+        .returns('http://acme.org/').twice();
+
+    setModeForTesting({});
+    const link = document.createElement('link');
+    link.setAttribute('rel', 'canonical');
+    link.setAttribute('href', 'https://foo.bar/baz');
+    document.head.appendChild(link);
+
+    const div = document.createElement('div');
+    div.setAttribute('type', '_ping_');
+    div.getLayoutBox = function() {
+      return {
+        width: 100,
+        height: 200,
+      };
+    };
+
+    const name = getIframe(window, div).name;
+    resetServiceForTesting(window, 'bootstrapBaseUrl');
+    resetCountForTesting();
+    const newName = getIframe(window, div).name;
+    expect(name).to.match(/d-\d+.ampproject.net__ping__0/);
+    expect(newName).to.match(/d-\d+.ampproject.net__ping__0/);
+    expect(newName).not.to.equal(name);
+  });
 });