diff --git a/context.plugins.inc b/context.plugins.inc
index 46dfac1..6f2b76d 100644
--- a/context.plugins.inc
+++ b/context.plugins.inc
@@ -83,11 +83,6 @@ function _context_context_registry() {
     );
   }
   $registry['reactions'] = array(
-    'block' => array(
-      'title' => t('Blocks'),
-      'description' => t('Control block visibility using context.'),
-      'plugin' => 'context_reaction_block',
-    ),
     'region' => array(
       'title' => t('Regions'),
       'description' => t('Control Region visiblity using context.'),
@@ -114,6 +109,13 @@ function _context_context_registry() {
       'plugin' => 'context_reaction_debug',
     ),
   );
+  if (module_exists('block')) {
+    $registry['reactions']['block'] = array(
+      'title' => t('Blocks'),
+      'description' => t('Control block visibility using context.'),
+      'plugin' => 'context_reaction_block',
+    );
+  }
   if (module_exists('menu')) {
     $registry['reactions']['menu'] = array(
       'title' => t('Menu'),