Peer support services (PSS) are an expanding part of the continuum of care provided for behavioral health conditions. These services have been deemed an evidence-based reimbursable model of care by the Centers for Medicare and Medicaid Services. States, counties, employers, and health plans are increasingly covering PSS in benefit plans. Controlled and experimental studies are building the evidence base for these services. Medicaid and the states have not developed level-of-care or medical necessity criteria for PSS, even though these criteria are standards for determining coverage and reimbursement. This review of emerging level-of-care criteria for PSS provides a framework for the further development of these resources.