Index: src/__celerity_resource_map__.php
===================================================================
--- src/__celerity_resource_map__.php
+++ src/__celerity_resource_map__.php
@@ -1949,6 +1949,20 @@
     ),
     'disk' => '/rsrc/js/application/owners/owners-path-editor.js',
   ),
+  'javelin-behavior-persona-login' =>
+  array(
+    'uri' => '/res/128fdf56/rsrc/js/application/auth/behavior-persona-login.js',
+    'type' => 'js',
+    'requires' =>
+    array(
+      0 => 'javelin-behavior',
+      1 => 'javelin-resource',
+      2 => 'javelin-stratcom',
+      3 => 'javelin-workflow',
+      4 => 'javelin-util',
+    ),
+    'disk' => '/rsrc/js/application/auth/behavior-persona-login.js',
+  ),
   'javelin-behavior-phabricator-active-nav' =>
   array(
     'uri' => '/res/9c8d3df8/rsrc/js/core/behavior-active-nav.js',
Index: src/__phutil_library_map__.php
===================================================================
--- src/__phutil_library_map__.php
+++ src/__phutil_library_map__.php
@@ -962,6 +962,7 @@
     'PhabricatorAuthProviderOAuthGoogle' => 'applications/auth/provider/PhabricatorAuthProviderOAuthGoogle.php',
     'PhabricatorAuthProviderOAuthTwitch' => 'applications/auth/provider/PhabricatorAuthProviderOAuthTwitch.php',
     'PhabricatorAuthProviderPassword' => 'applications/auth/provider/PhabricatorAuthProviderPassword.php',
+    'PhabricatorAuthProviderPersona' => 'applications/auth/provider/PhabricatorAuthProviderPersona.php',
     'PhabricatorAuthRegisterController' => 'applications/auth/controller/PhabricatorAuthRegisterController.php',
     'PhabricatorAuthStartController' => 'applications/auth/controller/PhabricatorAuthStartController.php',
     'PhabricatorAuthUnlinkController' => 'applications/auth/controller/PhabricatorAuthUnlinkController.php',
@@ -3116,6 +3117,7 @@
     'PhabricatorAuthProviderOAuthGoogle' => 'PhabricatorAuthProviderOAuth',
     'PhabricatorAuthProviderOAuthTwitch' => 'PhabricatorAuthProviderOAuth',
     'PhabricatorAuthProviderPassword' => 'PhabricatorAuthProvider',
+    'PhabricatorAuthProviderPersona' => 'PhabricatorAuthProvider',
     'PhabricatorAuthRegisterController' => 'PhabricatorAuthController',
     'PhabricatorAuthStartController' => 'PhabricatorAuthController',
     'PhabricatorAuthUnlinkController' => 'PhabricatorAuthController',
Index: src/applications/auth/provider/PhabricatorAuthProvider.php
===================================================================
--- src/applications/auth/provider/PhabricatorAuthProvider.php
+++ src/applications/auth/provider/PhabricatorAuthProvider.php
@@ -384,6 +384,7 @@
       array(
         'method' => 'optional string',
         'uri' => 'string',
+        'sigil' => 'optional string',
       ));
 
     $viewer = $request->getUser();
@@ -404,11 +405,11 @@
       ->setSpriteIcon($this->getLoginIcon());
 
     $button = id(new PHUIButtonView())
-        ->setSize(PHUIButtonView::BIG)
-        ->setColor(PHUIButtonView::GREY)
-        ->setIcon($icon)
-        ->setText($button_text)
-        ->setSubtext($this->getProviderName());
+      ->setSize(PHUIButtonView::BIG)
+      ->setColor(PHUIButtonView::GREY)
+      ->setIcon($icon)
+      ->setText($button_text)
+      ->setSubtext($this->getProviderName());
 
     $uri = $attributes['uri'];
     $uri = new PhutilURI($uri);
@@ -432,6 +433,7 @@
       array(
         'method' => idx($attributes, 'method', 'GET'),
         'action' => (string)$uri,
+        'sigil'  => idx($attributes, 'sigil'),
       ),
       $content);
   }
Index: src/applications/auth/provider/PhabricatorAuthProviderPersona.php
===================================================================
--- /dev/null
+++ src/applications/auth/provider/PhabricatorAuthProviderPersona.php
@@ -0,0 +1,79 @@
+<?php
+
+final class PhabricatorAuthProviderPersona
+  extends PhabricatorAuthProvider {
+
+  private $adapter;
+
+  public function getProviderName() {
+    return pht('Persona');
+  }
+
+  public function getDescriptionForCreate() {
+    return pht(
+      'Allow users to login or register using Mozilla Persona.');
+  }
+
+  public function getAdapter() {
+    if (!$this->adapter) {
+      $adapter = new PhutilAuthAdapterPersona();
+      $this->adapter = $adapter;
+    }
+    return $this->adapter;
+  }
+
+  protected function renderLoginForm(
+    AphrontRequest $request,
+    $mode) {
+
+    Javelin::initBehavior(
+      'persona-login',
+      array(
+        'loginURI' => $this->getLoginURI(),
+      ));
+
+    return $this->renderStandardLoginButton(
+      $request,
+      $mode,
+      array(
+        'uri' => $this->getLoginURI(),
+        'sigil' => 'persona-login-form',
+      ));
+  }
+
+  public function isLoginFormAButton() {
+    return true;
+  }
+
+  public function processLoginRequest(
+    PhabricatorAuthLoginController $controller) {
+
+    $request = $controller->getRequest();
+    $adapter = $this->getAdapter();
+
+    $account = null;
+    $response = null;
+
+    if (!$request->isAjax()) {
+      throw new Exception("Expected this request to come via Ajax.");
+    }
+
+    $assertion = $request->getStr('assertion');
+    if (!$assertion) {
+      throw new Exception("Expected identity assertion.");
+    }
+
+    $adapter->setAssertion($assertion);
+    $adapter->setAudience(PhabricatorEnv::getURI('/'));
+
+    try {
+      $account_id = $adapter->getAccountID();
+    } catch (Exception $ex) {
+      // TODO: Handle this in a more user-friendly way.
+      throw $ex;
+    }
+
+    return array($this->loadOrCreateAccount($account_id), $response);
+  }
+
+}
Index: webroot/rsrc/js/application/auth/behavior-persona-login.js
===================================================================
--- /dev/null
+++ webroot/rsrc/js/application/auth/behavior-persona-login.js
@@ -0,0 +1,41 @@
+/**
+ * @provides javelin-behavior-persona-login
+ * @requires javelin-behavior
+ *           javelin-resource
+ *           javelin-stratcom
+ *           javelin-workflow
+ *           javelin-util
+ */
+
+JX.behavior('persona-login', function(config) {
+
+  JX.Stratcom.listen(
+    'submit',
+    'persona-login-form',
+    function(e) {
+      e.kill();
+      navigator.id.request();
+    });
+
+  var onloaded = function() {
+    // Before installing watch(), log the user out, because we know they don't
+    // have a valid session if they're hitting this page. If we don't do this,
+    // Persona may immediately trigger a login event, which prevents the user
+    // from selecting another authentication mechanism.
+    navigator.id.logout();
+
+    navigator.id.watch({
+      loggedInUser: null,
+      onlogin: onlogin,
+      onlogout: JX.bag
+    });
+  };
+
+  var onlogin = function(assertion) {
+    new JX.Workflow(config.loginURI, {assertion: assertion})
+      .start();
+  };
+
+  var persona_library = 'https://login.persona.org/include.js';
+  JX.Resource.load(persona_library, onloaded);
+});