AbstractBackgroundLoneliness and social isolation have comparable health effects to widely acknowledged and established risk factors. Although old people are particularly affected, the effectiveness of interventions to prevent and/or mitigate social isolation and loneliness in the community-dwelling older adults is unclear. The aim of this review of reviews was to pool the findings of systematic reviews (SRs) addressing the question of effectiveness.MethodsOvid MEDLINE®, Health Evidence, Epistemonikos and Global Health (EBSCO) were searched from January 2017 to November 2021. Two reviewers independently assessed each SR in two consecutive steps based on previously defined eligibility criteria and appraised the methodological quality using a measurement tool to assess SRs 2, AMSTAR 2. One author extracted data from both SRs and eligible studies; another checked this. We conducted meta-analyses to pool the study results. We report the results of the random-effects and common-effect models.ResultsWe identified five SRs containing a total of 30 eligible studies, 16 with a low or moderate risk of bias. Our random-effects meta-analysis indicates an overall SMD effect of 0.63 [95% confidence interval (CI): −0.10 to 1.36] for loneliness and was unable to detect an overall effect of the interventions on social support [SMD: 0.00; 95% CI: −0.11 to 0.12].DiscussionThe results show interventions can potentially reduce loneliness in the non-institutionalized, community-dwelling and older population living at home. As confidence in the evidence is low, rigorous evaluation is recommended.RegistrationInternational Prospective Register of SRs (PROSPERO): Registration number: CRD42021255625