Purpose: Support groups are a common feature of the mental health support engaged by carers and consumers. The purpose of this paper is to update and consolidate the knowledge and the evidence for the effectiveness of mental health support groups. Design/methodology/approach: This paper is based on a systematic literature review of relevant databases around support groups for mental health. Support groups are defined as meetings of people with similar experiences, such as those defined as carers of a person living with a mental illness or a person living with a mental illness. These meetings aim to provide support and companionship to one another. Findings: The results show that there is a consistent pattern of evidence, over a long period of time, which confirms the effectiveness of mental health support groups for carers and people living with mental illness. There is strong, scientifically rigorous evidence which shows the effectiveness of professionally facilitated, family-led support groups, psychoeducation carers support groups, and professionally facilitated, program-based support groups for people living with mental illness. Research limitations/implications: This research implies the use of support groups is an important adjunct to the support of carers and people with mental illness, including severe mental illness. Originality/value: This research brings together a range of studies indicating the usefulness of support groups as an adjunct to mental health therapy.