Graduate medical education (GME) in Singapore recently underwent major reform (2009–2012), leading to accreditation of residency programs by the Accreditation Council for Graduate Medical Education–International (ACGME-I) within two years of the initial commitment to change. The main aims of the reforms were to implement best practices in GME, to provide better support structures for program administration, and to bring all specialty training under one administrative umbrella. The authors outline the historic development of GME in Singapore, the complexities of the model in place immediately prior to ACGME-I accreditation, and the difficulties addressed by the proposed changes, leading to a description of implementation efforts at the National University Hospital of Singapore, a university-affiliated academic medical center. The authors describe the institutional factors uniting hospital leaders in support of reform, the recruitment of a team to manage change within the institution, the inauguration of a new office for GME, and the faculty development initiatives needed to educate faculty leading the change process. The preparation and execution of specific initiatives designed to improve GME and the communication strategies needed to coordinate and publicize change efforts are outlined, as well as strategies for sustaining improvements and building them into the culture of the institution. The authors demonstrate that external accreditation can be a powerful driver of educational reform and summarize key lessons derived from Kotter principles, a current model of change management.