High prevalence of risk behaviours may exacerbate existing poor health in disadvantaged groups. We aimed to identify and bring together systematic reviews with a focus on reducing risk behaviours in disadvantaged groups and highlight where evidence is lacking. We searched MEDLINE and Embase up to October 2020, with supplementary searching in Epistemonikos and Health Systems Evidence. We included systematic reviews that reported behavioural outcomes and targeted smoking, excessive alcohol use, unhealthy diet, or physical inactivity in groups with the following characteristics: low income or low socio-economic status (SES), unemployed people, homeless people, care leavers, prisoners, refugees or asylum seeker, Travellers, Gypsies, or Roma, people with learning disabilities and people living in disadvantaged areas. Reviews that included primary studies from any high-income country were eligible. Reviews were mapped based on the disadvantaged group(s) and behaviour(s) targeted. Ninety-two reviews were included, with the majority (n=63) focusing on people with low income or low SES. We identified gaps in the evidence for care leavers; Gypsies, Travellers, and Roma and limited evidence for refugees and unemployed people. Few reviews targeted alcohol use. There was limited evidence on barriers and facilitators to behaviour change. This suggests there is insufficient evidence to inform policy and practice and new reviews or primary studies may be required.