diff --git a/providers/provider_data.go b/providers/provider_data.go
index 0e3f090f..fbea32a5 100644
--- a/providers/provider_data.go
+++ b/providers/provider_data.go
@@ -256,7 +256,8 @@ func (p *ProviderData) buildSessionFromClaims(rawIDToken, accessToken string) (*
 		{p.EmailClaim, &ss.Email},
 		{p.GroupsClaim, &ss.Groups},
 		// TODO (@NickMeves) Deprecate for dynamic claim to session mapping
-		{"preferred_username", &ss.PreferredUsername},
+		// NOTE(tommylike): for our ID server we decide to use "username" as our preferred_username source.
+		{"username", &ss.PreferredUsername},
 	} {
 		if _, err := extractor.GetClaimInto(c.claim, c.dst); err != nil {
 			return nil, err