As the number of adults with mental retardation and concomitant psychological difficulties living in the community increases, so does the need for effective outpatient psychotherapy services. Despite this need, the relevant literature base is sorely lacking. This article is a brief review of this literature with regard to psychodynamic, behavioral, and group psychotherapy approaches. On the basis of this review, a research agenda is offered concerning future directions. Last, because of the lack of a rich database regarding effective treatment approaches for such individuals, this article includes a description of a model of clinical decision making that is geared to aid the practicing clinician in designing clinical interventions for adults with mental retardation.