This chapter discusses the evaluation process from very specific perspectives. It addresses how to evaluate a therapist’s performance and how to evaluate the client’s experience in therapy, and then provides a more broadly-based approach to evaluating a program or agency. It focuses on social programs designed to provide for the mental health needs of their clientele. Evaluation can be defined as the systematic collection and analysis of information on the performance of a policy, program, or initiative to make judgments about relevance, progress or success and cost-effectiveness, and/or to inform future programming decisions about design and implementation. The American Evaluation Association (AEA) has developed a set of principles that are designed to guide evaluators in the conduct of their work. Ethics in any evaluation scenario can result in particularly thorny predicaments.