Individuals with autism spectrum disorder (ASD) are more susceptible to stress, anxiety and depression than typically developing individuals. Previous research suggests that mindfulness is effective in reducing a myriad of psychological health problems in a wide variety of populations. This review systematically investigated the efficacy of mindfulness interventions in reducing stress, anxiety, depression, rumination and aggression and increasing positive affect and psychological well-being in individuals with ASD. Six studies met inclusion criteria; each mindfulness program curriculum and process of delivery were analysed. A quality assessment rated three studies as weak, one as adequate and two as strong in research design strength. Results indicate that mindfulness training leads to a reduction in anxiety and thought problems in children in addition to increased social responsiveness, broad psychological well-being and reduced aggression in adolescents. Mindfulness training reduced anxiety, depression and rumination whilst increasing positive affect in adults with high-functioning ASD. The studies included a range of participants, methodologies and measures corroborating the robustness of mindfulness interventions resulting in positive psychological changes in individuals with ASD. Future research should address the methodological limitations of the studies in this review in order to develop superior mindfulness interventions that are to be considered evidence-based practice aimed at enhancing the quality of life of individuals with ASD.