This systematic review and meta-analysis examines the association between schizophrenia and other psychoses and violence, including homicide. The study searched bibliographic databases and reference lists from 1970 to February 2009 for studies reporting on the risks of interpersonal violence and/or violent criminality in individuals with schizophrenia and other psychoses compared to general population samples. Ten demographic and clinical variables were extracted from each study to test for heterogeneity in risk estimates. The review identified 20 individual studies reporting data from 18,423 individuals with schizophrenia and other psychoses. In men, odds ratios (ORs) for violence ranged from 1.0 to 5, with substantial heterogeneity (I² = 86%). In women, ORs ranged from 4 to 29, also with substantial heterogeneity (I² = 85%). Comorbid substance abuse significantly increased the risk of violence, with ORs of 1.95 (95% CI 1.7–2.7) without comorbidity and 2.95 (95% CI 5.4–14.7) with comorbidity (p<0.001 on metaregression). Risk estimates of violence in individuals with substance abuse (but without psychosis) were similar to those in individuals with psychosis and substance abuse comorbidity. The choice of outcome measure, study location, or period was not significantly associated with risk estimates. The risk of homicide was increased in individuals with psychosis (with and without comorbid substance abuse) compared to general population controls (random-effects OR = 19.5, 95% CI 14.7–25.8). The study concludes that schizophrenia and other psychoses are associated with violence and violent offending, particularly homicide, but most of the excess risk is mediated by substance abuse comorbidity. Public health strategies for violence reduction could focus on the primary and secondary prevention of substance abuse.This systematic review and meta-analysis examines the association between schizophrenia and other psychoses and violence, including homicide. The study searched bibliographic databases and reference lists from 1970 to February 2009 for studies reporting on the risks of interpersonal violence and/or violent criminality in individuals with schizophrenia and other psychoses compared to general population samples. Ten demographic and clinical variables were extracted from each study to test for heterogeneity in risk estimates. The review identified 20 individual studies reporting data from 18,423 individuals with schizophrenia and other psychoses. In men, odds ratios (ORs) for violence ranged from 1.0 to 5, with substantial heterogeneity (I² = 86%). In women, ORs ranged from 4 to 29, also with substantial heterogeneity (I² = 85%). Comorbid substance abuse significantly increased the risk of violence, with ORs of 1.95 (95% CI 1.7–2.7) without comorbidity and 2.95 (95% CI 5.4–14.7) with comorbidity (p<0.001 on metaregression). Risk estimates of violence in individuals with substance abuse (but without psychosis) were similar to those in individuals with psychosis and substance abuse comorbidity. The choice of outcome measure, study location, or period was not significantly associated with risk estimates. The risk of homicide was increased in individuals with psychosis (with and without comorbid substance abuse) compared to general population controls (random-effects OR = 19.5, 95% CI 14.7–25.8). The study concludes that schizophrenia and other psychoses are associated with violence and violent offending, particularly homicide, but most of the excess risk is mediated by substance abuse comorbidity. Public health strategies for violence reduction could focus on the primary and secondary prevention of substance abuse.