My research explored the relation between subordinate-state agency and hegemony. Most theories of hegemony in international relations assume an active role of, first, the hegemon, which upholds the hegemonic order, and, second, challenger states, which are powerful enough to threaten this order. Weaker, subordinate states are generally seen as passive objects and their agency and influence is largely unexplored in hegemony studies. This is surprising because subordinate-state consent, in most International Relations (IR) theories, forms an essential feature of hegemony. My project, therefore, questions subordinate-state passivity and, instead, connects consent to agency. It hypothesizes that subordinate-state agency is an underpinning element of hegemony, which will be strengthened if the hegemon heeds and addresses the interests of subordinate states, leading these to support it. When the hegemon fails to take subordinate-state interests into account, these states will effectively challenge and weaken hegemony.I tested the hypothesis by examining US hegemony in Latin America in the post-Cold War era, a period in which the United States established hegemony with significant levels of consent. Through process tracing, the project examines four case studies that fall within two themes of high relevance to contemporary US-Latin American relations. These are free-trade negotiations (Brazil and the FTAA; Peru and the US-PTPA) and counternarcotics cooperation (Plan Colombia; US-Bolivian relations during the Morales administration). Through this approach my research aspires to provide a nuanced understanding of the interactions between hegemonic and subordinate states in international relations and of the decisive influence subordinate states have within a hegemonic system.