diff --git a/lib/ansible/modules/system/user.py b/lib/ansible/modules/system/user.py
index 4b73057934..d8fad5c353 100644
--- a/lib/ansible/modules/system/user.py
+++ b/lib/ansible/modules/system/user.py
@@ -1028,7 +1028,7 @@ class OpenBSDUser(User):
         if self.groups is not None:
             current_groups = self.user_group_membership()
             groups_need_mod = False
-            groups_option = '-G'
+            groups_option = '-S'
             groups = []
 
             if self.groups == '':
@@ -1042,7 +1042,7 @@ class OpenBSDUser(User):
                     if self.append:
                         for g in groups:
                             if g in group_diff:
-                                groups_option = '-S'
+                                groups_option = '-G'
                                 groups_need_mod = True
                                 break
                     else: