Peer-delivered mental health models may hold important benefits for family members, yet their prevalence, components, and outcomes are unknown. We conducted a review of peer-delivered services for families of children and adults with mental health problems. Randomized studies of interventions published between 1990 and 2014 were included if the intervention contained a component for family members and examined familial outcomes. Of 77 studies that were assessed for their eligibility, six met criteria. Familial components included coping and parenting skills, knowledge about mental health, and emotional support. Outcomes were uneven, although significant improvements in family functioning, knowledge about mental illness, parental concerns about their child, and parenting skills were associated with the intervention. Peer-delivered services for family members may have important benefits to family members and individuals with mental health problems; however, the research base remains thin. A research agenda to develop and examine these models is discussed.