diff --git a/README.in b/README.in
index 6d5302975..85c71a73d 100644
--- a/README.in
+++ b/README.in
@@ -71,7 +71,7 @@ Notes about GLib 2.32
 
   or
 
-    G_MESSAGE_DEBUG=all
+    G_MESSAGES_DEBUG=all
 
 Notes about GLib 2.30
 =====================