Background: Poor social wellbeing is associated with health risks and excessive health care use. Identifying individuals at risk for poor social wellbeing and providing them with social care may improve their wellbeing, and also reduce costs from unnecessary health care utilization. Psychosocial interventions have been suggested to contribute to decreased health care use, however, such evidence has not been systematically quantified or synthesized. Objective: To systematically examine and meta-analyze all available evidence on the effect of psychosocial interventions on health care utilization. Methods: The databases Medline, Embase, PsycInfo, CINAHL, Cochrane and Scopus were searched in May 2021. Studies were included if they were randomised controlled trials that reported on health care utilisation and social wellbeing outcomes. A multi-level meta-analysis was used to derive pooled effects of interventions. Sub-group analyses examined participant- and intervention-level characteristics associated with intervention effects. Findings: Twenty-nine studies were included from 14,622 citations; 25 were eligible for meta-analysis. Data were analysed across 6357 participants, including older adults, post-natal women, people with chronic illnesses and caregivers. The overall effect was in favor of the intervention group, with 28% reduction in health care utilization [OR = 0.68; 95%CI = 0.48, 0.94]. Decreases in the use of emergency care, primary care and inpatient care were found. An improvement was observed in social support [SMD = 0.32; 95%CI = 0.04, 0.61]. Short (< 6 months), one-on-one interventions delivered by health professionals and interventions targeting caregivers had more favourable health care utilisation outcomes. A sustained reduction in inpatient care was observed for 6-12 months post-intervention. Conclusions: There is evidence that psychosocial interventions have the potential to reduce the burden on the health care system. Participant and intervention delivery characteristics, as well as intervention duration, could potentially affect outcomes and should be considered when designing and implementing future interventions.