Cognitive compensatory interventions aim to alleviate psychosocial disability by targeting functioning directly using aids and strategies, thereby minimizing the impact of cognitive impairment. The aim was to conduct a systematic review and meta-analysis of cognitive compensatory interventions for psychosis by examining the effects on functioning and symptoms, and exploring whether intervention factors, study design, and age influenced effect sizes.Electronic databases (Ovid Medline, PsychINFO) were searched up to October 2018. Records obtained through electronic and manual searches were screened independently by two reviewers according to selection criteria. Data were extracted to calculate estimated effects (Hedge’s g) of treatment on functioning and symptoms at post-intervention and follow-up. Study quality was assessed using Cochrane Collaboration’s risk of bias tool.Twenty-six studies, from 25 independent randomized controlled trials (RCTs) were included in the meta-analysis (1654 particiants, mean age=38.9 years, 64% male). Meta-analysis revealed a medium effect of compensatory interventions on functioning compared to control conditions (Hedge’s g = 0.46, 95% CI = 0.33, 0.60, P<.001), with evidence of relative durability at follow-up (Hedge’s g = 0.36, 95% CI = 0.19, 0.54, P<.001). Analysis also revealed small significant effects of cognitive compensatory treatment on negative, positive, and general psychiatric symptoms, but not depressive symptoms. Estimated effects did not significantly vary according to treatment factors (ie, compensatory approach, dosage), delivery method (ie, individual/group), age, or risk of bias. Longer treatment length was associated with larger effect sizes for functioning outcomes. No evidence of publication bias was identified.Cognitive compensatory interventions are associated with robust, durable improvements in functioning in people with psychotic illnesses.