The relationship between religiosity and mental health is a relatively well-researched field within North America, covering numerous domains of religiosity, including: religion, spirituality, prayer, church attendance, church affiliation and belief in God or a higher power. Considering the Australian literature, there are few papers that explore these dimensions of religiosity and their relationship with health, and in particular, very little research into the field of religiosity and mental health. Using systematic literature review methods, this study explores the Australian research into relationships between religiosity, mental health, and treatment outcomes for psychiatric illness and suicidal behaviour.