BACKGROUND: Acceptance- and mindfulness-based approaches have gained popularity in recent years. OBJECTIVE: A systematic review and meta-analysis of the efficacy and safety of acceptance- and mindfulness-based therapies for persons with a psychotic or schizophrenia spectrum disorder. METHODS: Following PRISMA guidelines, relevant databases were searched for published randomized controlled trials (RCTs) up to October 2018. Outcomes were severity of overall symptomatology, hospitalization, positive and negative symptoms, depression, anxiety, social functioning, quality of life, acceptance, mindfulness skills and safety of the interventions. RESULTS: Sixteen studies comprising 1268 people with a schizophrenia spectrum disorder were included in the meta-analyses. Moderate to large effect sizes were found for overall symptomatology and hospitalization at endpoint (SMD .80, 95% CI -1.31, -0.29 and MD 4.38, -5.58, -3.17 respectively) and follow-up (SMD 1.10, -2.09, -0.10 and MD 7.18, -8.67, - 5.68 respectively). There were significant small effects on negative symptoms (SMD .24; -0.44, -0.03), small to moderate effects for depression (SMD .47; -0.80, -0.14), social functioning (SMD .43; -0.75, - 0.12) and mindfulness (SMD .51; -0.97, -0.05), moderate to large effects for acceptance (SMD .78; -1.44, -0.12), while no significant effects for positive symptoms (SMD .27; -0.65, 0.00), anxiety (SMD 2.11; -4.64, 0.42) or quality of life (SMD .43; -0.88, 0.02). Majority of studies (75%) had low risk of bias and sensitivity analyses supported the findings. CONCLUSION: Acceptance- and mindfulness-based approaches appear to be effective and safe interventions for individuals with schizophrenia spectrum disorders and could be a useful extension of standard casemanagement and psychofarmacology.