diff --git a/lib/ecto/json.ex b/lib/ecto/json.ex
index 6ad19633ba..e08c98a73e 100644
--- a/lib/ecto/json.ex
+++ b/lib/ecto/json.ex
@@ -64,7 +64,7 @@ if Code.ensure_loaded?(JSON.Encoder) do
           defmodule #{inspect(owner)} do
             # ...
 
-            @derive {Jason.Encoder, only: [:name, :title, ...]}
+            @derive {JSON.Encoder, only: [:name, :title, ...]}
             schema ... do
 
       You can also use the :except option instead of :only if you would \