diff --git a/oci/spec_opts_unix.go b/oci/spec_opts_unix.go
index e42f61da1..5a6c66301 100644
--- a/oci/spec_opts_unix.go
+++ b/oci/spec_opts_unix.go
@@ -357,8 +357,8 @@ func WithUIDGID(uid, gid uint32) SpecOpts {
 
 // WithUserID sets the correct UID and GID for the container based
 // on the image's /etc/passwd contents. If /etc/passwd does not exist,
-// or uid is not found in /etc/passwd, it sets gid to be the same with
-// uid, and not returns error.
+// or uid is not found in /etc/passwd, it sets the requested uid,
+// additionally sets the gid to 0, and does not return an error.
 func WithUserID(uid uint32) SpecOpts {
 	return func(ctx context.Context, client Client, c *containers.Container, s *Spec) (err error) {
 		setProcess(s)