diff --git a/release.nix b/release.nix
index 70f3505b..0493a9e5 100644
--- a/release.nix
+++ b/release.nix
@@ -117,6 +117,7 @@ rec {
             CatalystViewJSON
             CatalystViewTT
             CatalystXScriptServerStarman
+            CryptJWT
             CryptRandPasswd
             DBDPg
             DBDSQLite
diff --git a/src/lib/Hydra/Controller/Root.pm b/src/lib/Hydra/Controller/Root.pm
index 12fbd530..dab82b62 100644
--- a/src/lib/Hydra/Controller/Root.pm
+++ b/src/lib/Hydra/Controller/Root.pm
@@ -14,10 +14,12 @@ use JSON;
 # Put this controller at top-level.
 __PACKAGE__->config->{namespace} = '';
 
+
 sub noLoginNeeded {
   my ($c) = @_;
 
   return $c->request->path eq "persona-login" ||
+         $c->request->path eq "google-login" ||
          $c->request->path eq "login" ||
          $c->request->path eq "logo" ||
          $c->request->path =~ /^static\//;
@@ -35,7 +37,6 @@ sub begin :Private {
     $c->stash->{tracker} = $ENV{"HYDRA_TRACKER"};
     $c->stash->{flashMsg} = $c->flash->{flashMsg};
     $c->stash->{successMsg} = $c->flash->{successMsg};
-    $c->stash->{personaEnabled} = $c->config->{enable_persona} // "0" eq "1";
 
     $c->stash->{isPrivateHydra} = $c->config->{private} // "0" ne "0";
 
@@ -69,6 +70,7 @@ sub begin :Private {
     }
 }
 
+
 sub deserialize :ActionClass('Deserialize') { }
 
 
diff --git a/src/lib/Hydra/Controller/User.pm b/src/lib/Hydra/Controller/User.pm
index 21476499..4d8d0b70 100644
--- a/src/lib/Hydra/Controller/User.pm
+++ b/src/lib/Hydra/Controller/User.pm
@@ -4,6 +4,7 @@ use utf8;
 use strict;
 use warnings;
 use base 'Hydra::Base::Controller::REST';
+use Crypt::JWT qw(decode_jwt);
 use Crypt::RandPasswd;
 use Digest::SHA1 qw(sha1_hex);
 use Hydra::Helper::Nix;
@@ -45,11 +46,63 @@ sub logout_POST {
 }
 
 
+sub doEmailLogin {
+    my ($self, $c, $type, $email, $fullName) = @_;
+
+    die "No email address provided.\n" unless defined $email;
+
+    # Be paranoid about the email address format, since we do use it
+    # in URLs.
+    die "Illegal email address.\n" unless $email =~ /^[a-zA-Z0-9\.\-\_]+@[a-zA-Z0-9\.\-\_]+$/;
+
+    # If persona_allowed_domains is set, check if the email address
+    # returned is on these domains.  When not configured, allow all
+    # domains.
+    my $allowed_domains = $c->config->{persona_allowed_domains} || "";
+    if ($allowed_domains ne "") {
+        my $email_ok = 0;
+        my @domains = split ',', $allowed_domains;
+        map { $_ =~ s/^\s*(.*?)\s*$/$1/ } @domains;
+
+        foreach my $domain (@domains) {
+            $email_ok = $email_ok || ((split '@', $email)[1] eq $domain);
+        }
+        error($c, "Your email address does not belong to a domain that is allowed to log in.\n")
+            unless $email_ok;
+    }
+
+    my $user = $c->find_user({ username => $email });
+
+    if ($user) {
+        # Automatically upgrade Persona accounts to Google accounts.
+        if ($user->type eq "persona" && $type eq "google") {
+            $user->update({type => "google"});
+        }
+
+        die "You cannot login via login type '$type'.\n" if $user->type ne $type;
+    } else {
+        $c->model('DB::Users')->create(
+            { username => $email
+            , fullname => $fullName,
+            , password => "!"
+            , emailaddress => $email,
+            , type => $type
+            });
+        $user = $c->find_user({ username => $email }) or die;
+    }
+
+    $c->set_authenticated($user);
+
+    $self->status_no_content($c);
+    $c->flash->{successMsg} = "You are now signed in as <tt>" . encode_entities($email) . "</tt>.";
+}
+
+
 sub persona_login :Path('/persona-login') Args(0) {
     my ($self, $c) = @_;
     requirePost($c);
 
-    error($c, "Persona support is not enabled.") unless $c->stash->{personaEnabled};
+    error($c, "Logging in via Persona is not enabled.") unless $c->config->{enable_persona};
 
     my $assertion = $c->stash->{params}->{assertion} or die;
 
@@ -64,42 +117,54 @@ sub persona_login :Path('/persona-login') Args(0) {
     my $d = decode_json($response->decoded_content) or die;
     error($c, "Persona says: $d->{reason}") if $d->{status} ne "okay";
 
-    my $email = $d->{email} or die;
+    doEmailLogin($self, $c, "persona", $d->{email}, undef);
+}
 
-    # Be paranoid about the email address format, since we do use it
-    # in URLs.
-    die "Illegal email address." unless $email =~ /^[a-zA-Z0-9\.\-\_]+@[a-zA-Z0-9\.\-\_]+$/;
 
-    # If persona_allowed_domains is set, check if the email address returned is on these domains.
-    # When not configured, allow all domains.
-    my $allowed_domains = $c->config->{persona_allowed_domains} || "";
-    if ( $allowed_domains ne "") {
-        my $email_ok = 0;
-        my @domains = split ',', $allowed_domains;
-        map { $_ =~ s/^\s*(.*?)\s*$/$1/ } @domains;
+# From https://www.googleapis.com/oauth2/v3/certs. Should probably not
+# hard-code this.
+my $googleKeys = <<'EOF';
+{
+ "keys": [
+  {
+   "kty": "RSA",
+   "alg": "RS256",
+   "use": "sig",
+   "kid": "10685afd5291883ce668345afd77201390406f82",
+   "n": "xeNopuszp35W6H1w2Tw4OrSwT8BZ9f7-2PoOyWZmfMmUDmYT2uxrZezDK0YLap5LVmpLNcpZP5Hj67_32NU3my4qfA-SlxuJMUxHWJF7Dqr-QNAqld0SZ_po4qz5ZTHDxNxoZ4iw_T-4lhIBGm0RIZprDDGPI7Vo8qIeIMjZywoh_nq32zB6tnjEUBvHcgay0qXEnQkKkavzHO_c5sLc1qXM0jDQVqyO1enevW2yA_8gP0Qb7014ycN5umCvEHc66c2_iNT-R4zgw8gd1g05n2xwyET8qb_3wi5LqUV-Cri4mJ2xwGY8uynlD2I4jVtOYJusBgNs6AfwyehzsLdwSQ",
+   "e": "AQAB"
+  },
+  {
+   "kty": "RSA",
+   "alg": "RS256",
+   "use": "sig",
+   "kid": "5a68fc8a3ec0c30e0be95aa08db99a68a725467f",
+   "n": "zmXvUwXYSo8VouhnkURp-3xywch-jPrk7q0gugqC7QIchBPnvdXdS-bj6sr1AqDl_hEDtiLGfiVr3Ft_U022rtHAl5n5NxyybUtZXWyT5yQZM4jopGBajavEUdCl9b4pqb-q_3fVaxUXe7re23sVjI5Bntd-8RYZ70tq-ZvCWBqsnz6lHi9Ditp3CZGWLMMBZlIv3nKnClOrZXL98Jmt7AAod-Gtk65saqnrMwWtBcI_Q-3u23ytywbMLanCeFFNUWlIOgZqyYYkOm-ylLRJzVaZ1THtcWILWCYUgxXjyF9DtXO3a8nct2JhdacD3LzRiPv3sXr31cg4arwUk19JoQ",
+   "e": "AQAB"
+  }
+ ]
+}
+EOF
 
-        foreach my $domain (@domains) {
-            $email_ok = $email_ok || ((split '@', $email)[1] eq $domain);
-        }
-        die "Email address is not allowed to login." unless $email_ok;
-    }
 
-    my $user = $c->find_user({ username => $email });
+sub google_login :Path('/google-login') Args(0) {
+    my ($self, $c) = @_;
+    requirePost($c);
 
-    if (!$user) {
-        $c->model('DB::Users')->create(
-            { username => $email
-            , password => "!"
-            , emailaddress => $email,
-            , type => "persona"
-            });
-        $user = $c->find_user({ username => $email }) or die;
-    }
+    error($c, "Logging in via Google is not enabled.") unless $c->config->{enable_google_login};
 
-    $c->set_authenticated($user);
+    my $data = decode_jwt(
+        token => ($c->stash->{params}->{id_token} // die "No token."),
+        kid_keys => $googleKeys,
+        verify_exp => 1,
+    );
 
-    $self->status_no_content($c);
-    $c->flash->{successMsg} = "You are now signed in as <tt>" . encode_entities($email) . "</tt>.";
+    die unless $data->{aud} eq $c->config->{google_client_id};
+    die unless $data->{iss} eq "accounts.google.com" || $data->{iss} eq "https://accounts.google.com";
+    die "Email address is not verified" unless $data->{email_verified};
+    # FIXME: verify hosted domain claim?
+
+    doEmailLogin($self, $c, "google", $data->{email}, $data->{name} // undef);
 }
 
 
diff --git a/src/root/auth.tt b/src/root/auth.tt
new file mode 100644
index 00000000..32e8ec58
--- /dev/null
+++ b/src/root/auth.tt
@@ -0,0 +1,108 @@
+[% IF c.user_exists  %]
+
+  <script>
+    function finishSignOut() {
+      $.post("[% c.uri_for('/logout') %]")
+        .done(function(data) {
+          window.location.reload();
+        })
+        .fail(function() { bootbox.alert("Server request failed!"); });
+    }
+
+    function signOut() {
+      [% IF c.user.type == 'google' %]
+        gapi.load('auth2', function() {
+          gapi.auth2.init();
+          var auth2 = gapi.auth2.getAuthInstance();
+          auth2.then(function () {
+            auth2.signOut().then(finishSignOut, finishSignOut);
+          });
+        });
+      [% ELSE %]
+        finishSignOut();
+      [% END %]
+    }
+  </script>
+
+[% ELSE %]
+
+  <div id="hydra-signin" class="modal hide fade" tabindex="-1" role="dialog" aria-hidden="true">
+    <form class="form-horizontal">
+      <div class="modal-body">
+        <div class="control-group">
+          <label class="control-label">User name</label>
+          <div class="controls">
+            <input type="text" class="span3" name="username" value=""/>
+          </div>
+        </div>
+        <div class="control-group">
+          <label class="control-label">Password</label>
+          <div class="controls">
+            <input type="password" class="span3" name="password" value=""/>
+          </div>
+        </div>
+      </div>
+      <div class="modal-footer">
+        <button id="do-signin" class="btn btn-primary">Sign in</button>
+        <button class="btn" data-dismiss="modal" aria-hidden="true">Cancel</button>
+      </div>
+    </form>
+  </div>
+
+  <script>
+
+    function finishSignOut() { }
+
+    $("#do-signin").click(function() {
+      requestJSON({
+        url: "[% c.uri_for('/login') %]",
+        data: $(this).parents("form").serialize(),
+        type: 'POST',
+        success: function(data) {
+          window.location.reload();
+        }
+      });
+      return false;
+    });
+
+  </script>
+
+  [% IF c.config.enable_google_login %]
+    <script>
+      function onGoogleSignIn(googleUser) {
+        requestJSON({
+          url: "[% c.uri_for('/google-login') %]",
+          data: "id_token=" + googleUser.getAuthResponse().id_token,
+          type: 'POST',
+          success: function(data) {
+            window.location.reload();
+          }
+        });
+        return false;
+      };
+    </script>
+  [% END %]
+
+[% END %]
+
+[% IF c.config.enable_persona %]
+  <script src="https://login.persona.org/include.js"></script>
+
+  <script>
+    navigator.id.watch({
+      onlogin: function(assertion) {
+        requestJSON({
+          url: "[% c.uri_for('/persona-login') %]",
+          data: "assertion=" + assertion,
+          type: 'POST',
+          success: function(data) { window.location.reload(); },
+          postError: function() { navigator.id.logout(); }
+        });
+      }
+    });
+
+    $("#persona-signin").click(function() {
+      navigator.id.request({ siteName: 'Hydra' });
+    });
+  </script>
+[% END %]
diff --git a/src/root/layout.tt b/src/root/layout.tt
index cf221cd1..684d696f 100644
--- a/src/root/layout.tt
+++ b/src/root/layout.tt
@@ -36,6 +36,11 @@
 
     <script type="text/javascript" src="[% c.uri_for("/static/js/common.js") %]"></script>
 
+    [% IF c.config.enable_google_login %]
+      <meta name="google-signin-client_id" content="[% c.config.google_client_id %]">
+      <script src="https://apis.google.com/js/platform.js" async="1" defer="1"></script>
+    [% END %]
+
     [% tracker %]
 
   </head>
@@ -94,95 +99,16 @@
         <small>
           <em><a href="http://nixos.org/hydra" target="_blank">Hydra</a> [% HTML.escape(version) %] (using [% HTML.escape(nixVersion) %]).</em>
           [% IF c.user_exists %]
-          You are signed in as <tt>[% HTML.escape(c.user.username) %]</tt>[% IF c.user.type == 'persona' %] via Persona[% END %].
+          You are signed in as <tt>[% HTML.escape(c.user.username) %]</tt>
+            [%- IF c.user.type == 'persona' %] via Persona
+            [%- ELSIF c.user.type == 'google' %] via Google[% END %].
           [% END %]
         </small>
       </footer>
 
     </div>
 
-    <script>
-      function doLogout() {
-        [% IF c.user_exists %]
-          $.post("[% c.uri_for('/logout') %]")
-            .done(function(data) {
-              window.location.reload();
-            })
-            .fail(function() { bootbox.alert("Server request failed!"); });
-        [% END %]
-      }
-    </script>
-
-    [% IF c.user_exists && c.user.type == 'hydra' %]
-      <script>
-        $("#persona-signout").click(doLogout);
-      </script>
-    [% ELSIF personaEnabled %]
-      <script src="https://login.persona.org/include.js"></script>
-
-      <script>
-        navigator.id.watch({
-          loggedInUser: [% c.user_exists ? '"' _ HTML.escape(c.user.username) _ '"' : "null" %],
-          onlogin: function(assertion) {
-            requestJSON({
-              url: "[% c.uri_for('/persona-login') %]",
-              data: "assertion=" + assertion,
-              type: 'POST',
-              success: function(data) { window.location.reload(); },
-              postError: function() { navigator.id.logout(); }
-            });
-          },
-          onlogout: doLogout
-        });
-
-        $("#persona-signin").click(function() {
-          navigator.id.request({ siteName: 'Hydra' });
-        });
-
-        $("#persona-signout").click(function() {
-          navigator.id.logout();
-        });
-      </script>
-    [% END %]
-
-    [% IF !c.user_exists %]
-      <div id="hydra-signin" class="modal hide fade" tabindex="-1" role="dialog" aria-hidden="true">
-        <form class="form-horizontal">
-          <div class="modal-body">
-            <div class="control-group">
-              <label class="control-label">User name</label>
-              <div class="controls">
-                <input type="text" class="span3" name="username" value=""/>
-              </div>
-            </div>
-            <div class="control-group">
-              <label class="control-label">Password</label>
-              <div class="controls">
-                <input type="password" class="span3" name="password" value=""/>
-              </div>
-            </div>
-          </div>
-          <div class="modal-footer">
-            <button id="do-signin" class="btn btn-primary">Sign in</button>
-            <button class="btn" data-dismiss="modal" aria-hidden="true">Cancel</button>
-          </div>
-        </form>
-      </div>
-
-      <script>
-          $("#do-signin").click(function() {
-            requestJSON({
-              url: "[% c.uri_for('/login') %]",
-              data: $(this).parents("form").serialize(),
-              type: 'POST',
-              success: function(data) {
-                window.location.reload();
-              }
-            });
-            return false;
-          });
-      </script>
-    [% END %]
+    [% PROCESS auth.tt %]
 
   </body>
 
diff --git a/src/root/topbar.tt b/src/root/topbar.tt
index e64069ce..14dba82a 100644
--- a/src/root/topbar.tt
+++ b/src/root/topbar.tt
@@ -127,24 +127,26 @@
   [% IF c.user_exists %]
     [% INCLUDE menuItem uri = c.uri_for(c.controller('User').action_for('edit'), [c.user.username]) title = "Preferences" %]
     <li>
-      <a href="#" id="persona-signout">Sign out</a>
+      <a href="#" onclick="signOut();">Sign out</a>
     </li>
   [% ELSE %]
-    [% IF personaEnabled %]
-      [% WRAPPER makeSubMenu title="Sign in" %]
+    [% WRAPPER makeSubMenu title="Sign in" %]
+      [% IF c.config.enable_google_login %]
+        <li>
+          <a><div class="g-signin2" data-onsuccess="onGoogleSignIn" data-theme="dark"></div></a>
+        </li>
+        <li class="divider"></li>
+      [% END %]
+      [% IF c.config.enable_persona %]
         <li>
           <a href="#" id="persona-signin">
             <img src="[% c.uri_for("/static/images/persona_sign_in_blue.png") %]" alt="Sign in with Persona" />
           </a>
         </li>
         <li class="divider"></li>
-        <li>
-          <a href="#hydra-signin" data-toggle="modal">Sign in with a Hydra account</a>
-        </li>
       [% END %]
-    [% ELSE %]
       <li>
-        <a href="#hydra-signin" data-toggle="modal">Sign in</a>
+        <a href="#hydra-signin" data-toggle="modal">Sign in with a Hydra account</a>
       </li>
     [% END %]
   [% END %]
diff --git a/src/root/user.tt b/src/root/user.tt
index 8f577929..3b7e8a73 100644
--- a/src/root/user.tt
+++ b/src/root/user.tt
@@ -53,7 +53,7 @@
     <div class="control-group">
       <label class="control-label">Email</label>
       <div class="controls">
-        <input type="text" class="span3" name="emailaddress" [% IF !create && user.type == 'persona' %]disabled="disabled"[% END %] [%+ HTML.attributes(value => user.emailaddress) %]/>
+        <input type="text" class="span3" name="emailaddress" [% IF !create && user.username.search('@') %]disabled="disabled"[% END %] [%+ HTML.attributes(value => user.emailaddress) %]/>
       </div>
     </div>