Opioid use disorder (OUD) is a chronic disease characterised by periods of abstinence and episodic return to use, that is associated with enormous socioeconomic burden and great risk for morbidity and mortality. Implementation of national opioid agonist treatment programs (OAT) has been an important strategy to respond to the opioid crisis tailored to each region. Heterogeneity across such programs and policies introduces a challenge in terms of harmonisation but also an opportunity for mutual learning and improvement. In this study, a convenience sample of 15 addiction medicine professionals were invited to complete an online questionnaire focused on challenges and strategies in delivering OAT in different countries and regions. Although national opioid treatment programs (OTP) were available in all but one country, important barriers were identified, and treatment coverage was overall low. In some countries, political and legislative changes are needed to improve public health responses and community attitudes towards persons with opioid use disorder (PWOUD). Providing evidence-based information to clinicians and individuals, strengthening the education of health professionals, and minimising stigma at different levels are seen as important steps that national and international institutions must take to address the opioid crisi