In this article, we present the hierarchical taxonomy of psychopathology (HiTOP), an evidence-based alternative to the categorical approach to diagnostic classification that has considerable promise for integrative psychotherapy research and practice. We first review issues associated with the categorical approach that may have constrained advances in psychotherapy. We next describe how the HiTOP model addresses some of these issues. We then offer suggestions regarding potentially mutual benefits of integrating HiTOP with treatment principles from the common factors literature as well as the cognitive-behavioral and relational psychotherapy traditions. We conclude by enumerating principles for psychotherapy research and practice based on the HiTOP model, which are illustrated with a case example.