diff --git a/core/lib/Drupal/Core/Template/TwigExtension.php b/core/lib/Drupal/Core/Template/TwigExtension.php
index bb29cd1..52bb06d 100644
--- a/core/lib/Drupal/Core/Template/TwigExtension.php
+++ b/core/lib/Drupal/Core/Template/TwigExtension.php
@@ -98,7 +98,8 @@ public function getFunctions() {
       new \Twig_SimpleFunction('url_from_path', array($this, 'getUrlFromPath'), array('is_safe_callback' => array($this, 'isUrlGenerationSafe'))),
       new \Twig_SimpleFunction('link', array($this, 'getLink')),
       new \Twig_SimpleFunction('file_url', 'file_create_url'),
-      new \Twig_SimpleFunction('attach_library', array($this, 'attachLibrary'))
+      new \Twig_SimpleFunction('attach_library', array($this, 'attachLibrary')),
+      new \Twig_SimpleFunction('active_theme_path', array($this, 'activeThemePath')),
     );
   }
 
@@ -443,4 +444,15 @@ public function renderVar($arg) {
     return $this->renderer->render($arg);
   }
 
+  /**
+   * Gets the path of the active theme.
+   *
+   * @return string
+   *   The path to the active theme.
+   */
+  public function activeThemePath() {
+    return \Drupal::service('theme.manager')->getActiveTheme()->getPath();
+
+  }
+
 }
diff --git a/core/modules/system/src/Tests/Theme/EngineTwigTest.php b/core/modules/system/src/Tests/Theme/EngineTwigTest.php
index ff84af7..64e125d 100644
--- a/core/modules/system/src/Tests/Theme/EngineTwigTest.php
+++ b/core/modules/system/src/Tests/Theme/EngineTwigTest.php
@@ -119,4 +119,13 @@ public function testTwigAttachLibrary() {
     $this->assertRaw('ckeditor.js');
   }
 
+  /**
+   * Tests the active_theme_path() function.
+   */
+  public function testActiveThemePath() {
+    $this->drupalGet('/twig-theme-test/active_theme_path');
+    $theme_path = \Drupal::service('theme.manager')->getActiveTheme()->getPath();
+    $this->assertRaw('<div>active theme path: ' . $theme_path . '</div>');
+  }
+
 }
diff --git a/core/modules/system/tests/modules/twig_theme_test/src/TwigThemeTestController.php b/core/modules/system/tests/modules/twig_theme_test/src/TwigThemeTestController.php
index 50d6c99..518d029 100644
--- a/core/modules/system/tests/modules/twig_theme_test/src/TwigThemeTestController.php
+++ b/core/modules/system/tests/modules/twig_theme_test/src/TwigThemeTestController.php
@@ -84,4 +84,11 @@ public function registryLoaderRender() {
     return array('#theme' => 'twig_registry_loader_test');
   }
 
+  /**
+   * Menu callback for testing the active theme path function.
+   */
+  public function activeThemePathRender() {
+    return array('#theme' => 'twig_theme_test_active_theme_path');
+  }
+
 }
diff --git a/core/modules/system/tests/modules/twig_theme_test/templates/twig_theme_test.active_theme_path.html.twig b/core/modules/system/tests/modules/twig_theme_test/templates/twig_theme_test.active_theme_path.html.twig
new file mode 100644
index 0000000..a52e326
--- /dev/null
+++ b/core/modules/system/tests/modules/twig_theme_test/templates/twig_theme_test.active_theme_path.html.twig
@@ -0,0 +1 @@
+<div>active theme path: {{ active_theme_path() }}</div>
diff --git a/core/modules/system/tests/modules/twig_theme_test/twig_theme_test.module b/core/modules/system/tests/modules/twig_theme_test/twig_theme_test.module
index 021d039..8462ba9 100644
--- a/core/modules/system/tests/modules/twig_theme_test/twig_theme_test.module
+++ b/core/modules/system/tests/modules/twig_theme_test/twig_theme_test.module
@@ -54,6 +54,10 @@ function twig_theme_test_theme($existing, $type, $theme, $path) {
     'variables' => array(),
     'template' => 'twig_theme_test.attach_library',
   );
+  $items['twig_theme_test_active_theme_path'] = array(
+    'variables' => array(),
+    'template' => 'twig_theme_test.active_theme_path',
+  );
   return $items;
 }
 
diff --git a/core/modules/system/tests/modules/twig_theme_test/twig_theme_test.routing.yml b/core/modules/system/tests/modules/twig_theme_test/twig_theme_test.routing.yml
index 4cdfeca..7bca891 100644
--- a/core/modules/system/tests/modules/twig_theme_test/twig_theme_test.routing.yml
+++ b/core/modules/system/tests/modules/twig_theme_test/twig_theme_test.routing.yml
@@ -55,3 +55,10 @@ twig_theme_test_registry_loader:
     no_cache: TRUE
   requirements:
     _access: 'TRUE'
+
+twig_theme_test_active_theme_path:
+  path: '/twig-theme-test/active_theme_path'
+  defaults:
+    _controller: '\Drupal\twig_theme_test\TwigThemeTestController::activeThemePathRender'
+  requirements:
+    _access: 'TRUE'