This presentation examines the role of evidence-based advocacy and civil society engagement in supporting legitimate policymaking, particularly in the context of drug policy and access to controlled medicines. It highlights persistent global inequities in opioid analgesic consumption and situates these disparities within international legal frameworks, including human rights instruments and drug control conventions. The presentation emphasizes the importance of civil society organizations and academia as key dialogue partners in multilateral governance processes. It argues that legitimate national policies require alignment with evidence-based normative frameworks, meaningful consultation with affected populations, and ongoing monitoring and evaluation. Civil society contributes to generating political consent, strengthening civic trust, and enhancing policy effectiveness. The presentation concludes that evidence-based policies are authoritative when they reflect social legitimacy, informed participation, and adherence to international legal and ethical standards.