It has been suggested that peers, or lay persons, should be more readily utilized in the provision of some mental health services, particularly in poor contexts where limited resources invariably result in many clients not receiving suitable and timely services. A systematic review and meta-analysis was conducted of all studies where peers were trained to implement some form of mental health service delivery to individuals resident in low- and middle-income countries (LMICS). The analyses of 14 eligible studies (n = 18,411 participants) revealed that depression and post-traumatic stress (PTS) were the most frequently assessed outcome measures. Overall effect sizes of small and medium magnitude were yielded for depression and PTS, respectively, suggesting that services delivered by peers may be efficacious in LMICS. While these results are encouraging, they are preliminary, and recommendations are made relating to the selection, training, and supervision of peers.