We examined the effectiveness of weight loss interventions in community-based settings for people with serious mental illness (SMI). METHOD: Four databases were searched for randomized controlled trials published in 2008 or later that met the criteria for the research question and used weight loss as an outcome measure. Data were extracted, and weight loss was analyzed using a meta-analysis. Similarities and differences in interventions were analyzed qualitatively. RESULTS: Seventeen studies and a total of 1,874 participants with various diagnoses of SMI were included in the meta-analysis. The various lifestyle-focused interventions had a significant effect on weight loss with an overall effect size of -0.308 (p < .001). CONCLUSION: Community-based interventions for people with SMI are effective for weight loss. Occupational therapists can be involved in the provision of weight loss interventions and in the development and study of intervention components that are most effective. CI - Copyright (c) 2018 by the American Occupational Therapy Association, Inc.