Problems with intimacy and interpersonal issues are exhibited across most psychiatric disorders. However, most of the targets in Cognitive Behavioral Therapy are primarily intrapersonal in nature, with few directly involved in interpersonal functioning and effective intimacy. Functional Analytic Psychotherapy (FAP) provides a behavioral basis for working on intimacy and interpersonal functioning. The current paper describes how intimacy concerns are addressed by FAP and provides evidence for the need to assess and understand the role of intimacy across a number of disorders. There are several justifications for support for including attempts to measure intimacy and design treatments to increase clients' effectiveness in intimacy. In conclusion, there appears to be a need to empirically determine the extent to which intimacy should be a therapeutic target of interest across many psychiatric disorders and FAP may be an important part of therapeutic change in these areas.