BACKGROUND: Mental health concerns in older adults are common, with increasing age-related risks to physical health, mobility and social isolation. Community-based approaches are a key focus of public health strategy in the UK, and may reduce the impact of these risks, protecting mental health and promoting wellbeing. We conducted a review of UK community-based interventions to understand the types of intervention studied and mental health/wellbeing impacts reported. METHOD: We conducted a scoping review of the literature, systematically searching six electronic databases (2000-2020) to identify academic studies of any non-clinical community intervention to improve mental health or wellbeing outcomes for older adults. Data were extracted, grouped by population targeted, intervention type, and outcomes reported, and synthesised according to a framework categorising community actions targeting older adults. RESULTS: In total, 1,131 full-text articles were assessed for eligibility and 54 included in the final synthesis. Example interventions included: link workers; telephone helplines; befriending; digital support services; group social activities. These were grouped into: connector services, gateway services/approaches, direct interventions and systems approaches. These interventions aimed to address key risk factors: loneliness, social isolation, being a caregiver and living with long-term health conditions. Outcome measurement varied greatly, confounding strong evidence in favour of particular intervention types. CONCLUSION: The literature is wide-ranging in focus and methodology. Greater specificity and consistency in outcome measurement are required to evidence effectiveness - no single category of intervention yet stands out as 'promising'. More robust evidence on the active components of interventions to promote older adult's mental health is required.