Abstract Background In the UK, the population of homelessness and housing insecurity is increasing among families headed by mothers. The unique stressors of housing insecurity and living in accommodations ill-suited to long-term dwellings increase mental distress for mothers and children. Community engagement interventions present a public health opportunity to alleviate adverse outcomes for vulnerable families. Aim To synthesise and evaluate evidence of the impact of community engagement interventions in supporting the mental well-being of mothers and children living under housing insecure conditions. To synthesise the components of community engagement interventions as a public health intervention in alleviating mental well-being and non-health outcomes of mothers and children living under housing insecurity. Methods A systematic search of five online bibliographic databases (MEDLINE, EMBASE, PsychINFO, Global Health and Child Development & Adolescent Studies) and grey literature (Carrot2) was conducted in May 2022. Primary studies with community engagement components and housing-insecure single-mother families were included. Intervention data was extracted using the TIDieR checklist and a community engagement keywording tool. The studies’ quality was critically appraised using the MetaQAT framework. Results Ten studies meeting inclusion criteria were identified, across two countries (USA & UK). Data from the studies reported positive significant effects for health and personal maternal outcomes in addition to higher positive effects for child health outcomes (e.g., decrease in depression symptoms). Interventions targeting social support and self-efficacy demonstrated potential to improve maternal and child outcomes via the maternal-child relationship. Community engagement at the design, delivery and evaluation intervention stages increased the level of community engagement, however there were tentative links to directly improving mental well-being outcomes. Conclusion There is evidence to suggest that community engagement may be applied as an effective intervention in supporting the mental well-being of mothers and children living under housing insecurity. Proposed intervention effectiveness may be achieved via psychosocial pathways such as improved maternal self-efficacy and social support. However, more embedded long-term process evaluations of these interventions are needed to establish maintenance of these observed benefits and to understand to what extent the findings apply to the UK context.