This study takes place in the largely rural Washington state prison system. This project tests two distinct strategies: first, a practical approach for screening for and diagnosing OUD.: Diagnosing OUD is a prerequisite to offering treatment, but identification of OUD in prisons is more challenging than in jails and non-carceral medical settings. This project is validating (a) a two-item OUD screening tool, intended for population-based screening, and (b) an 11-item diagnostic DSM-5 criteria OUD symptom checklist. Second, shared decision-making for OUD treatment options: After people are diagnosed with OUD, they need to make decisions about treatment. Treatment that aligns with an individual’s values and preferences may improve engagement and treatment outcomes. Shared decision-making (SDM) has been shown to increase treatment engagement for OUD and other behavioral health conditions. This project consists of a hybrid type 1 implementation-effectiveness encouragement trial of SDM for OUD treatment in a prison, randomizing people who are approaching release to be offered brief, nurse-led SDM or to receive usual care. The primary trial out- come is receipt of MOUD at release.