Clinical supervision is increasingly becoming one of the most prominent roles among psychologists ( Goodyear & Bernard, 1998 ;Goodyear & Guzzardo, 2000 ;Watkins, 1997 ). Supervision has a signifi cant infl uence on a clinician ' s training and professional development; it has an impact on the development of knowledge, skills, and competencies and promotes clinical effi cacy ( Cashwell & Dooley, 2001 ). Additionally, supervision is the central method used to ensure that clinicians provide quality care. Through training, support, consultation, and evaluation, clinical supervisors ensure that those entering psychology have the ability and values to perform competently. With the importance placed on supervision in provision of clinical services, it is important for psychologists to understand what supervision is and how it differs from psychotherapy and administration, the various roles involved in supervising clinicians, and the critical trends that will infl uence the conduct of supervision. Our goal for this chapter is to provide an overview of supervision and supervisory roles, the application of clinical supervision to the treatment of addiction, supervisory issues associated with diverse addiction treatment settings, and the provision of supervision within the addiction syndrome framework.