diff --git a/plugins/context_reaction_active_theme.inc b/plugins/context_reaction_active_theme.inc
index 8a77d1a..0c8e75e 100644
--- a/plugins/context_reaction_active_theme.inc
+++ b/plugins/context_reaction_active_theme.inc
@@ -39,7 +39,10 @@ class context_reaction_active_theme extends context_reaction {
     foreach (context_active_contexts() as $context) {
       if (!empty($context->reactions[$this->plugin]['theme'])) {
         global $custom_theme;
-        $custom_theme = $context->reactions[$this->plugin]['theme'];
+        global $user;
+        if (!$user->theme) {
+          $custom_theme = $context->reactions[$this->plugin]['theme'];
+        }
       }
     }
   }