AIMS: To explore how nurse practitioners experienced and understood development of their capability providing medication for opioid use disorder and safe supply in North American primary care settings. DESIGN: A phenomenographic approach was applied to the study design, recruitment, and analysis. METHODS: Semi-structured interviews were conducted with 21 nurse practitioners via Zoom between July and September 2022 to elicit participant experiences and understanding of capability development when treating opioid use disorder. Participants worked in primary care settings in New England, United States and Ontario, Canada. Data was analysed using a phenomenographic approach. RESULTS: Five categories of description representing conceptions of capability development in treating opioid use disorder were identified through iterative data analysis. Capability development was experienced as a process of developing foundational practice knowledge
integrating knowledge with existing practices
evolving practice perspectives
adaptation of practice and becoming expert. CONCLUSION: Capability attributes included creative thinking, risk taking and adapting existing practice in the service of person-centered care and harm reduction. IMPLICATIONS FOR THE PROFESSION AND PATIENT CARE: Nurse practitioners have potential to increase access to treatment for opioid use disorder and demonstrated ability and willingness to engage in this work. IMPACT: Nurse practitioners' participation as experts and leaders may be further leveraged in practice and policy development to enhance access to opioid use disorder treatment in primary care settings, including mentoring newer prescribers. REPORTING METHOD: Consolidated Criteria for Reporting Qualitative Studies (COREQ) EQUATOR guideline. PATIENT AND PUBLIC CONTRIBUTION: There were no patient or public contributions to this research study.