This chapter examines Hong Kong’s role in great power competition, echoing the theoretical agenda of this volume of questioning the state-centric assumption. Despite being a semiautonomous city rather than a state, Hong Kong has historically functioned as a site where global powers project influence. Its unique position as a capitalist enclave within socialist China enabled both the Washington and Beijing to leverage the city for purposes, affecting not only Hong Kong’s political trajectory but also wider geopolitical contests. The chapter first traces the emergence of Hong Kong’s territorial autonomy from Britain’s imperial decline, Cold War pressures, and the Chinese Communist Party’s strategic restraint, which together fostered its role as a “geopolitical buffer zone.” It then analyses Hong Kong as both an object of US-China rivalry and a subject exercising limited agency, before turning to the recent erosion of autonomy amid intensifying US-China competition.