Worldwide, governments spend trillions of dollars per year on the purchase of goods and services, commonly known as public procurement. The cumulative Ph.D. thesis investigates the causes, consequences and processes underlying international cooperation on public procurement, and hereby contributes to recent debates about the challenges facing the world trading system. The first paper provides a comparative historical analysis of international regime formation in public procurement and competition policy, addressing the wider question why some trade-related issues become integrated into the hard-law global trade regime, while others remain separated and governed through soft-law institutions. The second contribution investigates how global trade governance is transformed by the ascent of emerging economies, and focuses in particular on the domestic and international positioning of Brazil, India and China regarding public procurement regulation. Finally, the third study scrutinizes the effectiveness of international procurement agreements in promoting domestic procurement objectives such as the fight against corruption.