diff --git a/blocks/moodleblock.class.php b/blocks/moodleblock.class.php
index 205d68048d6..f0dab688e3b 100644
--- a/blocks/moodleblock.class.php
+++ b/blocks/moodleblock.class.php
@@ -418,8 +418,8 @@ class block_base {
      * @todo finish documenting this function
      */
     function applicable_formats() {
-        // Default case: the block can be used in all course types
-        return array('all' => true);
+        // Default case: the block can be used in all course types and not in quizzes
+        return array('all' => true, 'quiz' => false);
     }