Emergency department (ED)-based peer support programs aimed at linking persons with opioid use disorder (OUD) to medication for addiction treatment and other recovery services are a promising approach to addressing the opioid crisis. This brief report draws on experiences from three states' experience with such programs funded by the SAMHSA Opioid State Targeted Repose (STR) grants. Core functions of such programs include: Integration of peer supports in EDs; Alerting peers of eligible patients and making the patient aware of peer services; and connecting patients with recovery services. Qualitative data were analyzed using a general inductive approach conducted in 3 steps in order to identify forms utilized to fulfill these functions. Peer integration differed in terms of peer's physical location and who hired and supervised peers. Peers often depend on ED staff to alert them to potential patients while people other than the peers often first introduce potential patients to programming. Programs generally schedule initial appointments for recovery services for patients, but some programs provide a range of other services aimed at supporting participation in recovery services. Future effectiveness evaluations of ED-based peer support programs for OUD should consistently report on forms used to fulfill core functions.