diff --git a/main.go b/main.go
index fbead1e..0d55818 100644
--- a/main.go
+++ b/main.go
@@ -44,7 +44,7 @@ func main() {
 	flagSet.Bool("ssl-insecure-skip-verify", false, "skip validation of certificates presented when using HTTPS")
 
 	flagSet.Var(&emailDomains, "email-domain", "authenticate emails with the specified domain (may be given multiple times). Use * to authenticate any email")
-	flagSet.Var(&whitelistDomains, "whitelist-domains", "allowed domains for redirection after authentication")
+	flagSet.Var(&whitelistDomains, "whitelist-domain", "allowed domains for redirection after authentication")
 	flagSet.String("azure-tenant", "common", "go to a tenant-specific or common (tenant-independent) endpoint.")
 	flagSet.String("github-org", "", "restrict logins to members of this organisation")
 	flagSet.String("github-team", "", "restrict logins to members of this team")