diff --git a/GETTING_STARTED.md b/GETTING_STARTED.md
index 995f2c2..d4f28f4 100644
--- a/GETTING_STARTED.md
+++ b/GETTING_STARTED.md
@@ -187,6 +187,9 @@ user.first_name
 # => "Joe"
 ```
 
+Note that objects created with `build_stubbed` cannot be serialized with
+`Marshal.dump`, since factory_bot defines singleton methods on these objects.
+
 Static Attributes
 ------------------