This book constitutes the proceedings of the Second International Workshop on Emerging Technologies for Authorization and Authentication, ETAA 2019, held in Luxembourg, in September 2019. The 10 full papers presented in this volume were carefully reviewed and selected from numerous submissions. They focus on new techniques for biometric and behavioral based authentication, authentication and authorization in the IoT and in distributed systems in general, techniques for strengthen password based authentication and for dissuading malicious users from stolen password reuse, an approach for discovering authentication vulnerabilities in interconnected accounts, and strategies to optimize the access control decision process in the Big Data scenario.