diff --git a/wp-admin/includes/update-core.php b/wp-admin/includes/update-core.php
index c83f9698b8..85be7acc55 100644
--- a/wp-admin/includes/update-core.php
+++ b/wp-admin/includes/update-core.php
@@ -571,10 +571,11 @@ $_old_files = array(
 global $_new_bundled_files;
 
 $_new_bundled_files = array(
-'plugins/akismet/' => '2.0',
-'themes/twentyten/' => '3.0',
-'themes/twentyeleven/' => '3.2',
-'themes/twentytwelve/' => '3.5',
+	'plugins/akismet/'       => '2.0',
+	'themes/twentyten/'      => '3.0',
+	'themes/twentyeleven/'   => '3.2',
+	'themes/twentytwelve/'   => '3.5',
+	'themes/twentythirteen/' => '3.6',
 );
 
 /**
diff --git a/wp-admin/includes/upgrade.php b/wp-admin/includes/upgrade.php
index 64c9db09e9..56b9649351 100644
--- a/wp-admin/includes/upgrade.php
+++ b/wp-admin/includes/upgrade.php
@@ -218,7 +218,7 @@ As a new WordPress user, you should go to <a href=\"%s\">your dashboard</a> to d
 	update_option( 'widget_archives', array ( 2 => array ( 'title' => '', 'count' => 0, 'dropdown' => 0 ), '_multiwidget' => 1 ) );
 	update_option( 'widget_categories', array ( 2 => array ( 'title' => '', 'count' => 0, 'hierarchical' => 0, 'dropdown' => 0 ), '_multiwidget' => 1 ) );
 	update_option( 'widget_meta', array ( 2 => array ( 'title' => '' ), '_multiwidget' => 1 ) );
-	update_option( 'sidebars_widgets', array ( 'wp_inactive_widgets' => array (), 'sidebar-1' => array ( 0 => 'search-2', 1 => 'recent-posts-2', 2 => 'recent-comments-2', 3 => 'archives-2', 4 => 'categories-2', 5 => 'meta-2', ), 'sidebar-2' => array (), 'sidebar-3' => array (), 'array_version' => 3 ) );
+	update_option( 'sidebars_widgets', array ( 'wp_inactive_widgets' => array (), 'sidebar-1' => array ( 0 => 'search-2', 1 => 'recent-posts-2', 2 => 'recent-comments-2', 3 => 'archives-2', 4 => 'categories-2', 5 => 'meta-2', ), 'sidebar-2' => array (),'array_version' => 3 ) );
 
 	if ( ! is_multisite() )
 		update_user_meta( $user_id, 'show_welcome_panel', 1 );
diff --git a/wp-admin/nav-menus.php b/wp-admin/nav-menus.php
index 6c034f1024..0706b6c5d1 100644
--- a/wp-admin/nav-menus.php
+++ b/wp-admin/nav-menus.php
@@ -435,7 +435,7 @@ get_current_screen()->add_help_tab( array(
 'content'	=>
 	'<p>' . __('This feature allows you to use a custom menu in place of your theme&#8217;s default menus.') . '</p>' .
 	'<p>' . __('Custom menus may contain links to pages, categories, custom links or other content types (use the Screen Options tab to decide which ones to show on the screen). You can specify a different navigation label for a menu item as well as other attributes. You can create multiple menus. If your theme includes more than one menu location, you can choose which custom menu to associate with each. You can also use custom menus in conjunction with the Custom Menus widget.') . '</p>' .
-	'<p>' . sprintf( __('If your theme does not support the custom menus feature (the default themes, %1$s and %2$s, do), you can learn about adding this support by following the Documentation link to the side.'), 'Twenty Twelve', 'Twenty Eleven' ) . '</p>'
+	'<p>' . sprintf( __('If your theme does not support the custom menus feature (the default themes, %1$s and %2$s, do), you can learn about adding this support by following the Documentation link to the side.'), 'Twenty Thirteen', 'Twenty Twelve' ) . '</p>'
 ) );
 get_current_screen()->add_help_tab( array(
 'id'		=> 'create-menus',
diff --git a/wp-includes/class-wp-theme.php b/wp-includes/class-wp-theme.php
index ca105e881a..dfff7056c2 100644
--- a/wp-includes/class-wp-theme.php
+++ b/wp-includes/class-wp-theme.php
@@ -37,11 +37,12 @@ final class WP_Theme implements ArrayAccess {
 	 * @var array
 	 */
 	private static $default_themes = array(
-		'classic'      => 'WordPress Classic',
-		'default'      => 'WordPress Default',
-		'twentyten'    => 'Twenty Ten',
-		'twentyeleven' => 'Twenty Eleven',
-		'twentytwelve' => 'Twenty Twelve',
+		'classic'        => 'WordPress Classic',
+		'default'        => 'WordPress Default',
+		'twentyten'      => 'Twenty Ten',
+		'twentyeleven'   => 'Twenty Eleven',
+		'twentytwelve'   => 'Twenty Twelve',
+		'twentythirteen' => 'Twenty Thirteen',
 	);
 
 	/**
diff --git a/wp-includes/default-constants.php b/wp-includes/default-constants.php
index d7f6bbe1d1..358c1018f3 100644
--- a/wp-includes/default-constants.php
+++ b/wp-includes/default-constants.php
@@ -304,6 +304,6 @@ function wp_templating_constants() {
 	 * @since 3.0.0
 	 */
 	if ( !defined('WP_DEFAULT_THEME') )
-		define( 'WP_DEFAULT_THEME', 'twentytwelve' );
+		define( 'WP_DEFAULT_THEME', 'twentythirteen' );
 
 }