My work explores the United Nations Educational, Scientific and Cultural Organization’s (Unesco) attempt to use technical expertise to construct a peaceful and prosperous world community during the quarter-century following World War II. This was the period in which the institutional structures and functional norms of the modern international community were formed, and I analyze the reciprocal relationship between institutional structures and technical knowledge. My dissertation integrates historical research in archival and published primary sources with a rich interdisciplinary secondary literature to investigate the evolving role of science at Unesco. In the wake of WWII, Unesco’s founders intended the organization to marshal the objectivity of the scientific method to produce universal, value-neutral truths that transcended cultural and geographic boundaries to reveal the unity of mankind and thus provide the cultural foundation for a lasting peace. The pressures of the Cold War, decolonization, and the emergent imperative of international economic development transformed the organization’s mission. I focus on four scientific programs to analyze the effects of decolonization and the Cold War on Unesco’s programs and practices, and to assess how these historical processes shaped science in the international community. I explore how international organizations and experts framed problems so that they required technical intervention from the international community; how the institutional matrix of universities, research institutions, foundations, and state bureaucracies was reconfigured by Unesco’s and the United Nations’ activities; and how science and society were transformed when a traditionally European knowledge system was exported around the world.