This report summarizes the key findings of a project entitled “The Role of the Organization for Security and Co-operation in Europe (OSCE) in Security Sector Governance and Reform”, mandated by the Swiss Federal Department of Foreign Affairs with the support of the OSCE Secretary General. It consists of a mapping and comprehensive review of the OSCE’s role in supporting security sector governance and reform (SSG/R) at both normative and operational levels, and uses desk-based research complemented by interviews with over 170 interlocutors, including representatives of the OSCE Secretariat, institutions and field operations, national counterparts and members of the international community in four selected field contexts: Bosnia and Herzegovina, Kyrgyzstan, Serbia and Tajikistan.