Objective: Poor insight, or awareness of illness, has a negative impact on the outcome of the psychosis, and is therefore a logical target for treatment. A meta-analysis of the effect of psychological and pharmacological treatments on insight in psychosis was conducted to give a comprehensive overview of effective interventions. Methods: An inclusive literature search (1975-April 2012) was performed in PubMed, ISI Web of Science, and EMBASE. The search terms used were "Insight", "Awareness", "Treatment", "Psychosis", "Therapy" and "Schizophrenia", no language specified. A cross-reference search of eligible articles was performed to identify studies not found in the computerized search. Effect sizes (Cohen's d) of each study and overall were calculated under a random effects model with 95% confidence intervals. Results: Our literature search resulted in approximately 350 abstracts. Nineteen RCTs that examined treatment effects on insight in patients with psychotic disorders were included. Overall, the interventions had a medium effect (d=.34, 95% CI, 0.12-0.57). The effects of CBT, adherence therapy and psycho-education were small to moderate, but not significant, probably due to a lack of power. There were insufficient data to allow a statistical evaluation of the effect of skills training, medication, video-confrontation and comprehensive intervention programs consisting of multiple components. Few adverse effects on mood were documented but this aspect was seldom quantified. Conclusion: There is a paucity of studies providing data regarding treatment for impaired insight in psychosis. Nevertheless, from the published literature in this meta-analysis, we can confirm that it is a potential therapeutic target and that it is amenable to improvement. Comprehensive intervention programs consisting of multiple components may be particularly promising. Improvements in insight did not seem to be associated with increased depression.