Building an international evaluation community has the potential to strengthen the presence, practice, policies, and theories of evaluation and its contribution to improving the effectiveness of programs, policies, and services by making evaluation more rigorous, visible, and responsive to stakeholders. Following 7 years of work by evaluation leaders from many different countries, a major step toward realizing this vision occurred when the inaugural assembly of the International Organization for Cooperation in Evaluation (IOCE) was held in Lima Peru in March 2003. This article provides a rationale for the establishment of IOCE in terms of expected benefits, as well as a summary for the historical record of the challenges and opportunities that emerged in the process of planning such a complex undertaking, and the accomplishments of the IOCE to date. Finally, the road ahead for the IOCE is discussed.