diff --git a/includes/module.inc b/includes/module.inc
index 2e25108..a068569 100644
--- a/includes/module.inc
+++ b/includes/module.inc
@@ -193,8 +193,11 @@ function system_list($type) {
           foreach (array_keys($lists['theme'][$key]->base_themes) as $base_theme) {
             $lists['theme'][$base_theme]->sub_themes[$key] = $lists['theme'][$key]->info['name'];
           }
-          // Add the base theme's theme engine info.
-          $lists['theme'][$key]->info['engine'] = isset($lists['theme'][$base_key]->info['engine']) ? $lists['theme'][$base_key]->info['engine'] : 'theme';
+          // Add the base theme's theme engine info only when subtheme does not
+          // define one, this allows to use different theme engines.
+          if (!isset($lists['theme'][$key]->info['engine'])) {
+            $lists['theme'][$key]->info['engine'] = isset($lists['theme'][$base_key]->info['engine']) ? $lists['theme'][$base_key]->info['engine'] : 'theme';
+          }
         }
         else {
           // A plain theme is its own engine.
diff --git a/includes/theme.inc b/includes/theme.inc
index 9b606e9..9d160fd 100644
--- a/includes/theme.inc
+++ b/includes/theme.inc
@@ -139,7 +139,7 @@ function drupal_theme_initialize() {
  *   The callback to invoke to set the theme registry.
  */
 function _drupal_theme_initialize($theme, $base_theme = array(), $registry_callback = '_theme_load_registry') {
-  global $theme_info, $base_theme_info, $theme_engine, $theme_path;
+  global $theme_info, $base_theme_info, $theme_path;
   $theme_info = $theme;
   $base_theme_info = $base_theme;
 
@@ -201,37 +201,19 @@ function _drupal_theme_initialize($theme, $base_theme = array(), $registry_callb
     drupal_add_js($script, array('group' => JS_THEME, 'every_page' => TRUE));
   }
 
-  $theme_engine = NULL;
+  // Initialize all themes and engines.
+  // Make sure of loading the current theme first so preprocess functions are
+  // loaded properly.
+  foreach (array($theme) + list_themes() as $current) {
+    @include_once DRUPAL_ROOT . '/' . $current->owner;
 
-  // Initialize the theme.
-  if (isset($theme->engine)) {
-    // Include the engine.
-    include_once DRUPAL_ROOT . '/' . $theme->owner;
-
-    $theme_engine = $theme->engine;
-    if (function_exists($theme_engine . '_init')) {
-      foreach ($base_theme as $base) {
-        call_user_func($theme_engine . '_init', $base);
-      }
-      call_user_func($theme_engine . '_init', $theme);
-    }
-  }
-  else {
-    // include non-engine theme files
-    foreach ($base_theme as $base) {
-      // Include the theme file or the engine.
-      if (!empty($base->owner)) {
-        include_once DRUPAL_ROOT . '/' . $base->owner;
-      }
-    }
-    // and our theme gets one too.
-    if (!empty($theme->owner)) {
-      include_once DRUPAL_ROOT . '/' . $theme->owner;
+    if (function_exists($current->engine . '_init')) {
+      call_user_func($current->engine . '_init', $current);
     }
   }
 
   if (isset($registry_callback)) {
-    _theme_registry_callback($registry_callback, array($theme, $base_theme, $theme_engine));
+    _theme_registry_callback($registry_callback, array($theme, $base_theme));
   }
 }
 
@@ -304,8 +286,6 @@ function _theme_registry_callback($callback = NULL, array $arguments = array())
  * @param $base_theme
  *   An array of loaded $theme objects representing the ancestor themes in
  *   oldest first order.
- * @param $theme_engine
- *   The name of the theme engine.
  * @param $complete
  *   Whether to load the complete theme registry or an instance of the
  *   ThemeRegistry class.
@@ -313,7 +293,7 @@ function _theme_registry_callback($callback = NULL, array $arguments = array())
  * @return
  *   The theme registry array, or an instance of the ThemeRegistry class.
  */
-function _theme_load_registry($theme, $base_theme = NULL, $theme_engine = NULL, $complete = TRUE) {
+function _theme_load_registry($theme, $base_theme = NULL, $complete = TRUE) {
   if ($complete) {
     // Check the theme registry cache; if it exists, use it.
     $cached = cache_get("theme_registry:$theme->name");
@@ -322,7 +302,7 @@ function _theme_load_registry($theme, $base_theme = NULL, $theme_engine = NULL,
     }
     else {
       // If not, build one and cache it.
-      $registry = _theme_build_registry($theme, $base_theme, $theme_engine);
+      $registry = _theme_build_registry($theme, $base_theme);
       // Only persist this registry if all modules are loaded. This assures a
       // complete set of theme hooks.
       if (module_load_all(NULL)) {
@@ -672,10 +652,8 @@ function _theme_process_registry(&$cache, $name, $type, $theme, $path) {
  * @param $base_theme
  *   An array of loaded $theme objects representing the ancestor themes in
  *   oldest first order.
- * @param $theme_engine
- *   The name of the theme engine.
  */
-function _theme_build_registry($theme, $base_theme, $theme_engine) {
+function _theme_build_registry($theme, $base_theme) {
   $cache = array();
   // First, process the theme hooks advertised by modules. This will
   // serve as the basic registry. Since the list of enabled modules is the same
@@ -698,15 +676,15 @@ function _theme_build_registry($theme, $base_theme, $theme_engine) {
   foreach ($base_theme as $base) {
     // If the base theme uses a theme engine, process its hooks.
     $base_path = dirname($base->filename);
-    if ($theme_engine) {
-      _theme_process_registry($cache, $theme_engine, 'base_theme_engine', $base->name, $base_path);
+    if (isset($base->engine)) {
+      _theme_process_registry($cache, $base->engine, 'base_theme_engine', $base->name, $base_path);
     }
     _theme_process_registry($cache, $base->name, 'base_theme', $base->name, $base_path);
   }
 
   // And then the same thing, but for the theme.
-  if ($theme_engine) {
-    _theme_process_registry($cache, $theme_engine, 'theme_engine', $theme->name, dirname($theme->filename));
+  if (isset($theme->engine)) {
+    _theme_process_registry($cache, $theme->engine, 'theme_engine', $theme->name, dirname($theme->filename));
   }
 
   // Finally, hooks provided by the theme itself.
@@ -1167,16 +1145,14 @@ function theme($hook, $variables = array()) {
     $extension = '.tpl.php';
 
     // The theme engine may use a different extension and a different renderer.
-    global $theme_engine;
-    if (isset($theme_engine)) {
-      if ($info['type'] != 'module') {
-        if (function_exists($theme_engine . '_render_template')) {
-          $render_function = $theme_engine . '_render_template';
-        }
-        $extension_function = $theme_engine . '_extension';
-        if (function_exists($extension_function)) {
-          $extension = $extension_function();
-        }
+    if (isset($info['engine'])) {
+      $theme_engine = $info['engine'];
+      if (function_exists($theme_engine . '_render_template')) {
+        $render_function = $theme_engine . '_render_template';
+      }
+      $extension_function = $theme_engine . '_extension';
+      if (function_exists($extension_function)) {
+        $extension = $extension_function();
       }
     }
 
@@ -1309,10 +1285,21 @@ function drupal_find_theme_templates($cache, $extension, $path) {
   // used for filtering. This allows base themes to have sub-themes in its
   // folder hierarchy without affecting the base themes template discovery.
   $theme_paths = array();
-  foreach (list_themes() as $theme_info) {
+  $current_theme = NULL;
+  $current_engine = NULL;
+  foreach (list_themes() as $key => $theme_info) {
     if (!empty($theme_info->base_theme)) {
       $theme_paths[$theme_info->base_theme][$theme_info->name] = dirname($theme_info->filename);
     }
+    $theme_path = dirname($theme_info->filename);
+    if ($path === $theme_path) {
+      $current_theme = $current_theme;
+      $current_engine = isset($theme_info->engine) ? $theme_info->engine : NULL;
+    }
+    else if (!$current_theme && 0 === strpos($theme_path, $current_theme)) {
+      $current_theme = $current_theme;
+      $current_engine = isset($theme_info->engine) ? $theme_info->engine : NULL;
+    }
   }
   foreach ($theme_paths as $basetheme => $subthemes) {
     foreach ($subthemes as $subtheme => $subtheme_path) {
@@ -1349,6 +1336,7 @@ function drupal_find_theme_templates($cache, $extension, $path) {
     if (isset($cache[$hook])) {
       $implementations[$hook] = array(
         'template' => $template,
+        'engine' => $current_engine,
         'path' => dirname($file->uri),
       );
     }
@@ -1375,6 +1363,7 @@ function drupal_find_theme_templates($cache, $extension, $path) {
           $arg_name = isset($info['variables']) ? 'variables' : 'render element';
           $implementations[strtr($file, '-', '_')] = array(
             'template' => $file,
+            'engine' => $current_engine,
             'path' => dirname($files[$match]->uri),
             $arg_name => $info[$arg_name],
             'base hook' => $hook,
diff --git a/includes/theme.maintenance.inc b/includes/theme.maintenance.inc
index 6baf219..df8d446 100644
--- a/includes/theme.maintenance.inc
+++ b/includes/theme.maintenance.inc
@@ -87,8 +87,8 @@ function _drupal_maintenance_theme() {
 /**
  * Builds the registry when the site needs to bypass any database calls.
  */
-function _theme_load_offline_registry($theme, $base_theme = NULL, $theme_engine = NULL) {
-  return _theme_build_registry($theme, $base_theme, $theme_engine);
+function _theme_load_offline_registry($theme, $base_theme = NULL) {
+  return _theme_build_registry($theme, $base_theme);
 }
 
 /**
diff --git a/modules/simpletest/tests/theme.test b/modules/simpletest/tests/theme.test
index f5ddfa9..89f02f7 100644
--- a/modules/simpletest/tests/theme.test
+++ b/modules/simpletest/tests/theme.test
@@ -646,3 +646,78 @@ class ThemeDebugMarkupTestCase extends DrupalWebTestCase {
   }
 
 }
+
+/**
+ * Tests the multi theme engine support.
+ */
+class ThemeEngineNyanCatTestCase extends DrupalWebTestCase {
+  public static function getInfo() {
+    return array(
+      'name' => 'Theme engine test',
+      'description' => 'Tests the theme engine.',
+      'group' => 'Theme',
+    );
+  }
+
+  function setUp() {
+    parent::setUp('theme_test');
+    theme_enable(array('test_theme'));
+  }
+
+  /**
+   * Ensures a theme's template is overridable based on the 'template' filename.
+   */
+  function testTemplateOverride() {
+    variable_set('theme_default', 'test_theme_nyan_cat_engine');
+    variable_set('admin_theme', 'test_theme_nyan_cat_engine');
+
+    $this->drupalGet('theme-test/template-test-engine');
+    $this->assertText('Success: Template overridden with Nyan Cat theme. All of them', 'Template overridden by Nyan Cat file.');
+  }
+
+}
+
+/**
+ * Tests the multi theme engine support with a subtheme.
+ */
+class ThemeEngineNyanCatSubThemeTestCase extends DrupalWebTestCase {
+  public static function getInfo() {
+    return array(
+      'name' => 'Sub theme engine test',
+      'description' => 'Tests the theme engine on a subtheme.',
+      'group' => 'Theme',
+    );
+  }
+
+  function setUp() {
+    parent::setUp('theme_test');
+    theme_enable(array('test_theme'));
+  }
+
+  /**
+   * Ensures a theme's template is overridable based on the 'template' filename.
+   */
+  function testTemplateOverride() {
+    variable_set('theme_default', 'test_subtheme_nyan_cat_engine');
+    variable_set('admin_theme', 'test_subtheme_nyan_cat_engine');
+
+    $this->drupalGet('theme-test/template-test-engine');
+    $this->assertText('Success: Template overridden with Nyan Cat theme. All of them', 'Template overridden by Nyan Cat file.');
+  }
+
+  /**
+   * Ensure the subtheme has inherited of the theme engine of it's base theme.
+   */
+  function testEngineIsCorrectlyInherited() {
+    $infos = list_themes();
+
+    // Get the base theme name from the theme 'test_subtheme_nyan_cat_engine'
+    $base_theme_name = $infos['test_subtheme_nyan_cat_engine']->info['base theme'];
+    // Get the base theme
+    $base_theme = $infos[$base_theme_name];
+
+    // Compare their theme engine.
+    $this->assertEqual($infos['test_subtheme_nyan_cat_engine']->info['engine'], $base_theme->info['engine']);
+  }
+
+}
diff --git a/modules/simpletest/tests/theme_test.module b/modules/simpletest/tests/theme_test.module
index 948d817..6518e04 100644
--- a/modules/simpletest/tests/theme_test.module
+++ b/modules/simpletest/tests/theme_test.module
@@ -17,6 +17,10 @@ function theme_test_theme($existing, $type, $theme, $path) {
   $items['theme_test_foo'] = array(
     'variables' => array('foo' => NULL),
   );
+  $items['theme_test_template_test_engine'] = array(
+    'template' => 'theme_test.template_test_engine',
+    'engine' => 'nyan_cat'
+  );
   return $items;
 }
 
@@ -27,10 +31,20 @@ function theme_test_system_theme_info() {
   $themes['test_theme'] = drupal_get_path('module', 'theme_test') . '/themes/test_theme/test_theme.info';
   $themes['test_basetheme'] = drupal_get_path('module', 'theme_test') . '/themes/test_basetheme/test_basetheme.info';
   $themes['test_subtheme'] = drupal_get_path('module', 'theme_test') . '/themes/test_subtheme/test_subtheme.info';
+  $themes['test_theme_nyan_cat_engine'] = drupal_get_path('module', 'theme_test') . '/themes/test_theme_nyan_cat_engine/test_theme_nyan_cat_engine.info';
+  $themes['test_subtheme_nyan_cat_engine'] = drupal_get_path('module', 'theme_test') . '/themes/test_subtheme_nyan_cat_engine/test_subtheme_nyan_cat_engine.info';
   return $themes;
 }
 
 /**
+ * Implements hook_system_theme_info().
+ */
+function theme_test_system_theme_engine_info() {
+  $theme_engines['nyan_cat'] = drupal_get_path('module', 'theme_test') . '/themes/engines/nyan_cat/nyan_cat.engine';
+  return $theme_engines;
+}
+
+/**
  * Implements hook_menu().
  */
 function theme_test_menu() {
@@ -58,10 +72,25 @@ function theme_test_menu() {
     'access callback' => TRUE,
     'type' => MENU_CALLBACK,
   );
+  $items['theme-test/template-test-engine'] = array(
+    'page callback' => '_theme_test_template_test_engine',
+    'access callback' => TRUE,
+    'type' => MENU_CALLBACK,
+  );
+
   return $items;
 }
 
 /**
+ * Page callback, calls a theme hook suggestion.
+ */
+function _theme_test_template_test_engine() {
+  return array(
+    '#markup' => theme('theme_test_template_test_engine', array()),
+  );
+}
+
+/**
  * Implements hook_init().
  */
 function theme_test_init() {
diff --git a/modules/system/system.api.php b/modules/system/system.api.php
index 3152139..f1855b9 100644
--- a/modules/system/system.api.php
+++ b/modules/system/system.api.php
@@ -2051,6 +2051,22 @@ function hook_system_theme_info() {
 }
 
 /**
+ * Return additional theme engines provided by modules.
+ *
+ * This hook is invoked from _system_rebuild_theme_data() and allows modules to
+ * register additional theme engines outside of the regular 'themes/engines'
+ * directories of a Drupal installation.
+ *
+ * @return
+ *   An associative array. Each key is the system name of a theme engine and
+ *   each value is the corresponding path to the theme engine's .engine file.
+ */
+function hook_system_theme_engine_info() {
+  $theme_engines['izumi'] = drupal_get_path('module', 'mymodule') . '/izumi/izumi.engine';
+  return $theme_engines;
+}
+
+/**
  * Alter the information parsed from module and theme .info files
  *
  * This hook is invoked in _system_rebuild_module_data() and in
diff --git a/modules/system/system.module b/modules/system/system.module
index 59087c8..4a5c0d4 100644
--- a/modules/system/system.module
+++ b/modules/system/system.module
@@ -30,7 +30,7 @@ define('DRUPAL_USER_TIMEZONE_EMPTY', 1);
  */
 define('DRUPAL_USER_TIMEZONE_SELECT', 2);
 
- /**
+/**
  * Disabled option on forms and settings
  */
 define('DRUPAL_DISABLED', 0);
@@ -2041,7 +2041,7 @@ function system_user_timezone(&$form, &$form_state) {
 function system_block_info() {
   $blocks['main'] = array(
     'info' => t('Main page content'),
-     // Cached elsewhere.
+    // Cached elsewhere.
     'cache' => DRUPAL_NO_CACHE,
     // Auto-enable in 'content' region by default, which always exists.
     // @see system_themes_page(), drupal_render_page()
@@ -2505,6 +2505,9 @@ function _system_update_bootstrap_status() {
  *   An associative array of themes information.
  */
 function _system_rebuild_theme_data() {
+  // Find theme engines
+  $engines = drupal_system_listing('/^' . DRUPAL_PHP_FUNCTION_PATTERN . '\.engine$/', 'themes/engines');
+
   // Find themes
   $themes = drupal_system_listing('/^' . DRUPAL_PHP_FUNCTION_PATTERN . '\.info$/', 'themes');
   // Allow modules to add further themes.
@@ -2519,8 +2522,17 @@ function _system_rebuild_theme_data() {
     }
   }
 
-  // Find theme engines
-  $engines = drupal_system_listing('/^' . DRUPAL_PHP_FUNCTION_PATTERN . '\.engine$/', 'themes/engines');
+  // As Drupal is not able to find theme engines in modules, then, we allow
+  // users to add theme engines through a module hook.
+  if ($module_themes = module_invoke_all('system_theme_engine_info')) {
+    foreach ($module_themes as $name => $theme_engine_path) {
+      $engines[$name] = (object) array(
+        'uri' => $theme_engine_path,
+        'filename' => basename($theme_engine_path),
+        'name' => $name,
+      );
+    }
+  }
 
   // Set defaults for theme info.
   $defaults = array(
@@ -2563,6 +2575,7 @@ function _system_rebuild_theme_data() {
     $type = 'theme';
     drupal_alter('system_info', $themes[$key]->info, $themes[$key], $type);
 
+
     if (!empty($themes[$key]->info['base theme'])) {
       $sub_themes[] = $key;
     }
@@ -2605,9 +2618,15 @@ function _system_rebuild_theme_data() {
     foreach (array_keys($themes[$key]->base_themes) as $base_theme) {
       $themes[$base_theme]->sub_themes[$key] = $themes[$key]->info['name'];
     }
+
+    if ($themes[$key]->info['engine'] != $themes[$base_key]->info['engine']) {
+      $themes[$key]->info['engine'] = $themes[$base_key]->info['engine'];
+      unset($themes[$key]->owner);
+    }
+
     // Copy the 'owner' and 'engine' over if the top level theme uses a theme
-    // engine.
-    if (isset($themes[$base_key]->owner)) {
+    // engine and the current theme has no engine itself.
+    if (isset($themes[$base_key]->owner) && !isset($themes[$key]->owner)) {
       if (isset($themes[$base_key]->info['engine'])) {
         $themes[$key]->info['engine'] = $themes[$base_key]->info['engine'];
         $themes[$key]->owner = $themes[$base_key]->owner;