The present article summarizes the assumptions, model, techniques, evidence, and diversity/social justice commitments of Acceptance and Commitment Therapy (ACT). ACT focused on six processes (acceptance, defusion, self, now, values, and action) that bear on a single overall target (psychological flexibility). The ACT model of behavior change has been shown to have positive outcomes across a broad range of applied problems and areas of growth. Process and outcome evidence suggest that the psychological flexibility model underlying ACT provides a unified model of behavior change and personal development that fits well with the core assumptions of counseling psychology. (Contains 1 figure.)