Since the 1990s, scholars have paid attention to the role of social movements traversing the official terrain of politics by blending a “contention” strategy with an “engagement” strategy. The literature often highlights the contribution of institutionalized social movements to policymaking and sociopolitical change, but rarely addresses why and how specific social movement organizations gain routine access to formal politics. Using the Korean women's movement as a case study, I analyze the conditions for movement institutionalization. As I perceive it as the consequence both of social movements' decision to participate in government and of the state's desire to integrate such movements into its decision-making process, movement institutionalization appears when the three factors are combined: (1) pressure from international organizations, (2) democratizing political structures, and (3) cognitive shifts by movement activists toward the role of the state.