This systematic review evaluates the evidence for the effectiveness of interventions within the scope of occupational therapy to improve and maintain performance and participation for people with serious mental illness. Areas included in this review are activities of daily living, instrumental activities of daily living, leisure, social participation, and rest and sleep. METHOD: Databases searched included MEDLINE, PsycINFO, CINAHL, OTseeker, and the Cochrane Database of Systematic Reviews. Reviewers read and assessed citations, abstracts, and full-text articles for inclusion and analysis. RESULTS: Sixty-one articles were selected for inclusion. The review yielded strong evidence for psychoeducation and occupation- and cognitive-based interventions, moderate evidence for skills-based interventions, and limited evidence for technology-supported interventions. CONCLUSION: Results of this review support use of evidence-based practice within the scope of occupational therapy, inclusion of occupational therapy practitioners as mental health service providers, and continued research. CI - Copyright (c) 2018 by the American Occupational Therapy Association, Inc.