diff --git a/docs/en/reference/second-level-cache.rst b/docs/en/reference/second-level-cache.rst
index d07cf0869..03d5b6de4 100644
--- a/docs/en/reference/second-level-cache.rst
+++ b/docs/en/reference/second-level-cache.rst
@@ -447,6 +447,8 @@ It caches the primary keys of association and cache each element will be cached
                 usage : NONSTRICT_READ_WRITE
 
 
+> Note: for this to work, the target entity must also be marked as cacheable.
+
 Cache usage
 ~~~~~~~~~~~