diff --git a/src/AuthenticationClient.ts b/src/AuthenticationClient.ts
index bcc7841..0330dce 100644
--- a/src/AuthenticationClient.ts
+++ b/src/AuthenticationClient.ts
@@ -715,7 +715,7 @@ export class AuthenticationClient {
       nonce,
     };
     if (options?.tenantId) {
-      params.tenantId = options?.tenantId;
+      params.tenant_id = options?.tenantId;
     }
     if (options?.forced) {
       params.prompt = "login";
diff --git a/src/AuthenticationClientInterface.ts b/src/AuthenticationClientInterface.ts
index 32ca830..cd4984a 100644
--- a/src/AuthenticationClientInterface.ts
+++ b/src/AuthenticationClientInterface.ts
@@ -13,7 +13,7 @@ export interface AuthURLParams {
   nonce: string;
   scope: string;
   prompt?: string;
-  tenantId?: string;
+  tenant_id?: string;
 }
 
 export interface OIDCTokenResponse {