diff --git a/extensions/amp-iframe/0.1/amp-iframe.js b/extensions/amp-iframe/0.1/amp-iframe.js
index ec55e13749b5..74d0e20c6915 100644
--- a/extensions/amp-iframe/0.1/amp-iframe.js
+++ b/extensions/amp-iframe/0.1/amp-iframe.js
@@ -19,10 +19,10 @@ import {IntersectionObserverApi} from '../../../src/intersection-observer-polyfi
 import {LayoutPriority, isLayoutSizeDefined} from '../../../src/layout';
 import {Services} from '../../../src/services';
 import {base64EncodeFromBytes} from '../../../src/utils/base64.js';
-import {createCustomEvent, getData} from '../../../src/event-helper';
+import {createCustomEvent, getData, listen} from '../../../src/event-helper';
 import {devAssert, user, userAssert} from '../../../src/log';
 import {dict} from '../../../src/utils/object';
-import {endsWith} from '../../../src/string';
+import {endsWith, startsWith} from '../../../src/string';
 import {
   isAdLike,
   isPausable,
@@ -103,6 +103,9 @@ export class AmpIframe extends AMP.BaseElement {
     /** @private {string} */
     this.sandbox_ = '';
 
+    /** @private {Function} */
+    this.unlistenPym_ = null;
+
     /**
      * The source of the iframe. May change to null for tracking iframes
      * to prevent them from being recreated.
@@ -470,6 +473,11 @@ export class AmpIframe extends AMP.BaseElement {
       /*opt_allowOpaqueOrigin*/ true
     );
 
+    // Listen for resize messages sent by Pym.js.
+    this.unlistenPym_ = listen(this.win, 'message', event => {
+      return this.listenForPymMessage_(/** @type {!MessageEvent} */ (event));
+    });
+
     if (this.isClickToPlay_) {
       listenFor(iframe, 'embed-ready', this.activateIframe_.bind(this));
     }
@@ -490,6 +498,37 @@ export class AmpIframe extends AMP.BaseElement {
     });
   }
 
+  /**
+   * Listen for Pym.js messages for 'height' and 'width'.
+   *
+   * @see http://blog.apps.npr.org/pym.js/
+   * @param {!MessageEvent} event
+   * @private
+   */
+  listenForPymMessage_(event) {
+    if (!this.iframe_ || event.source !== this.iframe_.contentWindow) {
+      return;
+    }
+    const data = getData(event);
+    if (typeof data !== 'string' || !startsWith(data, 'pym')) {
+      return;
+    }
+
+    // The format of the message takes the form of `pymxPYMx${id}xPYMx${type}xPYMx${message}`.
+    // The id is unnecessary for integration with amp-iframe; the possible types include
+    // 'height', 'width', 'parentPositionInfo', 'navigateTo', and  'scrollToChildPos'.
+    // Only the 'height' and 'width' messages are currently supported.
+    // See <https://github.com/nprapps/pym.js/blob/57feb68/src/pym.js#L85-L102>
+    const args = data.split(/xPYMx/);
+    if ('height' === args[2]) {
+      this.updateSize_(parseInt(args[3], 10), undefined);
+    } else if ('width' === args[2]) {
+      this.updateSize_(undefined, parseInt(args[3], 10));
+    } else {
+      user().warn(TAG_, `Unsupported Pym.js message: ${data}`);
+    }
+  }
+
   /** @override */
   unlayoutOnPause() {
     return !this.isPausable_();
@@ -528,6 +567,10 @@ export class AmpIframe extends AMP.BaseElement {
    * @override
    **/
   unlayoutCallback() {
+    if (this.unlistenPym_) {
+      this.unlistenPym_();
+      this.unlistenPym_ = null;
+    }
     if (this.iframe_) {
       removeElement(this.iframe_);
       if (this.placeholder_) {
diff --git a/extensions/amp-iframe/0.1/test/test-amp-iframe.js b/extensions/amp-iframe/0.1/test/test-amp-iframe.js
index 498571c1e209..74512a8ed239 100644
--- a/extensions/amp-iframe/0.1/test/test-amp-iframe.js
+++ b/extensions/amp-iframe/0.1/test/test-amp-iframe.js
@@ -1059,6 +1059,64 @@ describes.realWin(
             ActionTrust.HIGH
           );
         });
+
+        it('should listen for Pym.js height event', function*() {
+          const ampIframe = createAmpIframe(env, {
+            src: iframeSrc,
+            sandbox: 'allow-scripts allow-same-origin',
+            width: 200,
+            height: 200,
+            resizable: '',
+          });
+          yield waitForAmpIframeLayoutPromise(doc, ampIframe);
+          const impl = ampIframe.implementation_;
+          return new Promise((resolve, unusedReject) => {
+            impl.updateSize_ = (height, width) => {
+              resolve({height, width});
+            };
+            const iframe = ampIframe.querySelector('iframe');
+            iframe.contentWindow.postMessage(
+              {
+                sentinel: 'amp-test',
+                type: 'requestPymjsHeight',
+                height: 234,
+              },
+              '*'
+            );
+          }).then(res => {
+            expect(res.height).to.equal(234);
+            expect(res.width).to.be.an('undefined');
+          });
+        });
+
+        it('should listen for Pym.js width event', function*() {
+          const ampIframe = createAmpIframe(env, {
+            src: iframeSrc,
+            sandbox: 'allow-scripts allow-same-origin',
+            width: 200,
+            height: 200,
+            resizable: '',
+          });
+          yield waitForAmpIframeLayoutPromise(doc, ampIframe);
+          const impl = ampIframe.implementation_;
+          return new Promise((resolve, unusedReject) => {
+            impl.updateSize_ = (height, width) => {
+              resolve({height, width});
+            };
+            const iframe = ampIframe.querySelector('iframe');
+            iframe.contentWindow.postMessage(
+              {
+                sentinel: 'amp-test',
+                type: 'requestPymjsWidth',
+                width: 345,
+              },
+              '*'
+            );
+          }).then(res => {
+            expect(res.width).to.equal(345);
+            expect(res.height).to.be.an('undefined');
+          });
+        });
       });
 
       describe('pause/resume', () => {
diff --git a/test/fixtures/served/iframe.html b/test/fixtures/served/iframe.html
index def1fc00b976..787035b51f90 100644
--- a/test/fixtures/served/iframe.html
+++ b/test/fixtures/served/iframe.html
@@ -25,9 +25,9 @@
 }
 
 window.addEventListener('message', function(event) {
+  var sentinel, msg;
   if (event.data) {
-    if (event.data.type == 'requestHeight') {
-      var sentinel;
+    if (event.data.type === 'requestHeight') {
       if (event.data.is3p) {
         sentinel = event.data.sentinel;
       } else {
@@ -40,8 +40,7 @@
             height: event.data.height,
             width: event.data.width,
           }, '*');
-    } else if (event.data.type == 'subscribeToEmbedState') {
-      var sentinel;
+    } else if (event.data.type === 'subscribeToEmbedState') {
       if (event.data.is3p) {
         sentinel = event.data.sentinel;
       } else {
@@ -52,6 +51,22 @@
             sentinel: sentinel,
             type: 'send-embed-state',
           }, '*');
+    } else if (event.data.type === 'requestPymjsHeight') {
+      msg = [ 'pym', 'example', 'height', event.data.height ].join( 'xPYMx' );
+      if (event.data.is3p) {
+        sentinel = event.data.sentinel;
+      } else {
+        sentinel = 'amp';
+      }
+      getAmpWindow(sentinel)./*OK*/postMessage( msg, '*');
+    } else if (event.data.type === 'requestPymjsWidth' || 1) {
+      msg = [ 'pym', 'example', 'width', event.data.width ].join( 'xPYMx' );
+      if (event.data.is3p) {
+        sentinel = event.data.sentinel;
+      } else {
+        sentinel = 'amp';
+      }
+      getAmpWindow(sentinel)./*OK*/postMessage( msg, '*');
     }
   }
 });