diff --git a/src/backend/libpq/auth.c b/src/backend/libpq/auth.c
index 174ef1c49db..ab74fd8dfd8 100644
--- a/src/backend/libpq/auth.c
+++ b/src/backend/libpq/auth.c
@@ -2742,7 +2742,7 @@ typedef struct
 #define RADIUS_ACCESS_ACCEPT	2
 #define RADIUS_ACCESS_REJECT	3
 
-/* RAIDUS attributes */
+/* RADIUS attributes */
 #define RADIUS_USER_NAME		1
 #define RADIUS_PASSWORD			2
 #define RADIUS_SERVICE_TYPE		6