Previous research agendas have prioritised the role of biological determinants in mental illness aetiology. This is of particular concern, as endorsing biological determinants has been shown to promote negative attitudes towards people with mental illness. The aim of this review was to provide an overview of high-quality evidence of the social determinants of mental illness. A rapid review of systematic reviews was conducted. Five databases were searched: Embase, Medline, Academic Search Complete, CINAHL Plus, and PsycINFO. Systematic reviews or meta-analyses that described any social determinant of mental illness, were published in peer-review journals in English, and focussed on human participants were included. The Preferred Reporting Items for Systematic Review and Meta-Analyses (PRISMA) guidelines were applied for the selection procedure. Thirty-seven systematic reviews were deemed eligible for review and narrative synthesis. Determinants identified included conflict, violence and maltreatment, life events and experiences, racism and discrimination, culture and migration, social interaction and support, structural policies and inequality, financial factors, employment factors, housing and living conditions, and demographic factors. We recommend that mental health nurses ensure adequate support be provided to those affected by the evidenced social determinants of mental illness.