This chapter describes the complex medicolegal issues surrounding the rules of confidentiality and privilege and their multiple exceptions. It lays out the underpinnings of confidentiality, then addresses its various exceptions, such as waiver, duty to protect third parties, civil commitment, and mandated reporting of child abuse, elder abuse, and intimate-partner violence. Psychotherapist–patient privilege is discussed, first with regard to its origins and then with regard to its exceptions, including various forms of waiver. Practical examples illustrate these concepts for the reader to make it easier to understand these ubiquitous, but at times perplexing, concepts and to illustrate the nuances of various aspects of the law. Practitioners should note that there is considerable overlap between confidentiality and testimonial privilege, and the division of this chapter into two sections creates, in some ways, an artificial divide between two closely related concepts.