Key PointsQuestionWhat is the association between hospitals attesting to an emergency department buprenorphine treatment Opioid Hospital Quality Improvement Program (O-HQIP) pathway and patients’ subsequent initiation of buprenorphine treatment?FindingsIn this cohort study using difference-in-differences analyses of 17 428 Medicaid-enrolled adults with an opioid use disorder emergency department encounter, the buprenorphine treatment O-HQIP pathway was associated with significantly increased prescription fills for buprenorphine within 30 days of discharge.MeaningThis study’s findings suggest that the O-HQIP may be a new policy approach to expanding access to evidence-based treatment for opioid use disorder.