Abstract. The European Diploma in Psychology defines a common European standard for the competences required to practice as a psychologist. This paper describes how that standard was developed and defined, and why it was considered important to bring together the traditional input-based specification of professional competence, in terms of curriculum and training course content, with a more outcome-oriented approach that focuses on the competences that a professional psychologist needs to demonstrate in practice. The paper addresses three specific questions. What are the competences that a psychologist should possess? Are these competences the same for all areas of practice within professional psychology? How can these competences be assessed?