diff --git a/advagg_mod/advagg_mod.admin.inc b/advagg_mod/advagg_mod.admin.inc
index d23c779..b981467 100644
--- a/advagg_mod/advagg_mod.admin.inc
+++ b/advagg_mod/advagg_mod.admin.inc
@@ -332,6 +332,12 @@ function advagg_mod_admin_settings_form() {
       '@link' => 'http://stackoverflow.com/questions/19374843/css-delivery-optimization-how-to-defer-css-loading',
     )),
   );
+  $form['css']['placement']['expert']['advagg_mod_css_defer_admin'] = array(
+    '#type' => 'checkbox',
+    '#title' => t('Use JS to load CSS in the admin theme'),
+    '#default_value' => variable_get('advagg_mod_css_defer_admin', ADVAGG_MOD_CSS_DEFER_ADMIN),
+    '#description' => t('This will optimize CSS delivery with JavaScript when viewing the admin theme'),
+  );
   $form['css']['placement']['expert']['advagg_mod_css_defer_js_code'] = array(
     '#type' => 'radios',
     '#title' => t('How to include the JS loading code'),
diff --git a/advagg_mod/advagg_mod.module b/advagg_mod/advagg_mod.module
index 80209e2..b075047 100644
--- a/advagg_mod/advagg_mod.module
+++ b/advagg_mod/advagg_mod.module
@@ -77,6 +77,11 @@ define('ADVAGG_MOD_CSS_ADJUST_SORT_BROWSERS', FALSE);
 define('ADVAGG_MOD_CSS_DEFER', FALSE);
 
 /**
+ * Default value to use JavaScript to defer CSS loading in the admin theme.
+ */
+define('ADVAGG_MOD_CSS_DEFER_ADMIN', FALSE);
+
+/**
  * Default value to move CSS into drupal_add_css().
  */
 define('ADVAGG_MOD_CSS_HEAD_EXTRACT', FALSE);
@@ -698,6 +703,13 @@ function advagg_mod_advagg_modify_css_pre_render_alter(&$children, &$elements) {
   if (empty($css_defer)) {
     return;
   }
+
+  // Return early if we're in the admin theme and this setting is disabled.
+  $css_defer_admin = variable_get('advagg_mod_css_defer_admin', ADVAGG_MOD_CSS_DEFER_ADMIN);
+  if (empty($css_defer_admin) && path_is_admin(current_path())) {
+    return;
+  }
+
   $css_defer_js_code = variable_get('advagg_mod_css_defer_js_code', ADVAGG_MOD_CSS_DEFER_JS_CODE);
 
   // Make advagg_mod_loadStyleSheet() available.