--- a/mobile/android/components/extensions/ext-pageAction.js
+++ b/mobile/android/components/extensions/ext-pageAction.js
@@ -1,15 +1,18 @@
 /* -*- Mode: indent-tabs-mode: nil; js-indent-level: 2 -*- */
 /* vim: set sts=2 sw=2 et tw=80: */
 "use strict";
 
 XPCOMUtils.defineLazyModuleGetter(this, "EventEmitter",
                                   "resource://devtools/shared/event-emitter.js");
 
+XPCOMUtils.defineLazyModuleGetter(this, "Services",
+                                  "resource://gre/modules/Services.jsm");
+
 // Import the android PageActions module.
 XPCOMUtils.defineLazyModuleGetter(this, "PageActions",
                                   "resource://gre/modules/PageActions.jsm");
 
 Cu.import("resource://gre/modules/ExtensionUtils.jsm");
 
 var {
   SingletonEventManager,
@@ -23,17 +26,25 @@ function PageAction(options, extension) 
 
   let DEFAULT_ICON = "data:image/png;base64,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";
 
   this.options = {
     title: options.default_title || extension.name,
     icon: DEFAULT_ICON,
     id: extension.id,
     clickCallback: () => {
-      this.emit("click");
+      if (this.default_popup) {
+        let win = Services.wm.getMostRecentWindow("navigator:browser");
+        win.BrowserApp.addTab(this.default_popup, {
+          selected: true,
+          parentId: win.BrowserApp.selectedTab.id
+        });
+      } else {
+        this.emit("click");
+      }
     },
   };
 
   EventEmitter.decorate(this);
 }
 
 PageAction.prototype = {
   show(tabId) {
@@ -80,14 +91,15 @@ extensions.registerSchemaAPI("pageAction
         return () => {
           pageActionMap.get(extension).off("click", listener);
         };
       }).api(),
 
       show(tabId) {
         pageActionMap.get(extension).show(tabId);
       },
+
       hide(tabId) {
         pageActionMap.get(extension).hide(tabId);
       },
     },
   };
 });

--- a/mobile/android/components/extensions/schemas/page_action.json
+++ b/mobile/android/components/extensions/schemas/page_action.json
@@ -19,17 +19,16 @@
                 "preprocess": "localize"
               },
               "default_icon": {
                 "unsupported": true,
                 "$ref": "IconPath",
                 "optional": true
               },
               "default_popup": {
-                "unsupported": true,
                 "type": "string",
                 "format": "relativeUrl",
                 "optional": true,
                 "preprocess": "localize"
               },
               "browser_style": {
                 "type": "boolean",
                 "optional": true

--- a/mobile/android/components/extensions/test/mochitest/chrome.ini
+++ b/mobile/android/components/extensions/test/mochitest/chrome.ini
@@ -1,5 +1,6 @@
 [DEFAULT]
 support-files =
   head.js
 
-[test_ext_pageAction.html]
\ No newline at end of file
+[test_ext_pageAction.html]
+[test_ext_pageAction_defaultPopup.html]
\ No newline at end of file

new file mode 100644
--- /dev/null
+++ b/mobile/android/components/extensions/test/mochitest/test_ext_pageAction_popup.html
@@ -0,0 +1,100 @@
+<!DOCTYPE HTML>
+<html>
+<head>
+  <title>PageAction Test</title>
+  <script src="chrome://mochikit/content/tests/SimpleTest/SimpleTest.js"></script>
+  <script src="chrome://mochikit/content/tests/SimpleTest/SpawnTask.js"></script>
+  <script src="chrome://mochikit/content/tests/SimpleTest/ExtensionTestUtils.js"></script>
+  <script type="text/javascript" src="head.js"></script>
+  <link rel="stylesheet" href="chrome://mochikit/contents/tests/SimpleTest/test.css"/>
+</head>
+<body>
+
+<script type="text/javascript">
+"use strict";
+
+Cu.import("resource://gre/modules/Services.jsm");
+
+add_task(function* test_contentscript() {
+  function backgroundScript() {
+    // TODO: Use the Tabs API to obtain the tab ids for showing pageActions.
+    let tabId = 1;
+    browser.test.onMessage.addListener(msg => {
+      if (msg === "page-action-show") {
+        // TODO: switch to using .show(tabId).then(...) once bug 1270742 lands.
+        browser.pageAction.show(tabId);
+        browser.test.sendMessage("page-action-shown");
+      } else if (msg == "page-action-close-popup") {
+        browser.runtime.sendMessage("close-popup");
+      }
+    });
+
+    browser.pageAction.onClicked.addListener(tab => {
+      browser.test.fail(`The onClicked listener should never fire when a popup is shown.`);
+    });
+
+    browser.test.sendMessage("ready");
+  }
+
+  function popupScript() {
+    window.onload = () => {
+      browser.test.sendMessage("from-page-action-popup-shown");
+    };
+    browser.runtime.onMessage.addListener(msg => {
+      if (msg == "close-popup") {
+        window.close();
+      }
+    });
+  }
+
+  let extension = ExtensionTestUtils.loadExtension({
+    background: `(${backgroundScript}())`,
+    manifest: {
+      "name": "PageAction Extension",
+      "page_action": {
+        "default_title": "Page Action",
+        "default_popup": "popup.html",
+      },
+    },
+    files: {
+      "popup.html": `<html><head><meta charset="utf-8"><script src="popup.js"></${"script"}></head></html>`,
+      "popup.js": `(${popupScript})()`,
+    },
+  });
+
+  let tabClosedPromise = new Promise(resolve => {
+    let chromeWin = Services.wm.getMostRecentWindow("navigator:browser");
+    let BrowserApp = chromeWin.BrowserApp;
+
+    let tabCloseListener = (event) => {
+      BrowserApp.deck.removeEventListener("TabClose", tabCloseListener, false);
+      let browser = event.target;
+      let url = browser.currentURI.spec
+      resolve(url);
+    }
+
+    BrowserApp.deck.addEventListener("TabClose", tabCloseListener, false);
+  });
+
+  yield extension.startup();
+  yield extension.awaitMessage("ready");
+
+  extension.sendMessage("page-action-show");
+  yield extension.awaitMessage("page-action-shown");
+  ok(isPageActionShown(extension.id), "The PageAction should be shown");
+
+  clickPageAction(extension.id);
+  yield extension.awaitMessage("from-page-action-popup-shown");
+
+  extension.sendMessage("page-action-close-popup");
+
+  let url = yield tabClosedPromise;
+  ok(url.includes("popup.html"), "The tab for the popup should be closed");
+
+  yield extension.unload();
+  ok(!isPageActionShown(extension.id), "The PageAction should be removed after unload");
+});
+</script>
+
+</body>
+</html>