OBJECTIVE: This systematic review summarises the current state of research on mindfulness in SPMI, given the pressing need to provide alternative, scalable and cost-effective treatment modalities for patients with severe and persistent mental illness (SPMI). METHODS: Articles included mindfulness-based interventions for SPMI. Excluded articles included qualitative studies, acceptance and compassion therapies, case reports and reviews. Studies were identified by searching the databases Medline, Embase and PsycINFO. RESULTS: Six randomised controlled trials, seven prospective studies and one retrospective study were identified. Clinical improvements were observed on psychotic symptoms, and on improvements of depression symptoms, cognition, mindfulness, psycho-social and vocational factors. CONCLUSIONS: Findings suggest that mindfulness is feasible for individuals with SPMI, and displays potential benefits in outcomes aside from psychotic symptoms. The effects of mindfulness in psychotic symptoms needs further investigation in larger definitive studies using methodological rigor and thorough assessments of other psychiatric populations who are also representative of SPMI.