RecruitingBehavioural interventionNavSTAR Implementation Effectiveness Trial Across a Health SystemPatient Navigation (PN) interventions following hospitalization can improve outcomes for people with opioid use disorder treatment. Delivering PN interventions on a wide scale requires many resources and coordination across institutions. This will use an evidence-based process to find solutions to these significant barriers by engaging community, hospital, and patient partners. This study is being conducted to learn more about how to implement NavSTAR, a patient navigation intervention for people with opioid use disorder, across a health system. The research team showed in a previous study with 400 participants that NavSTAR significantly increased entry into opioid use disorder treatment, reduced readmissions to the hospital, and was highly cost- effective compared to treatment as usual. This study will first pilot NavSTAR with 32 patient participants across 4 hospitals in the City of Philadelphia. Then, a large trial with 720 patient participants will be conducted to see if people who need the intervention are reached, and a sustainable plan will be created to continue the intervention after the grant award period.