The recognition of same-sex marriage in Costa Rica constitutes one of the most significant milestones in the recent history of LGBTIQ human rights in the region. However, far from being an isolated event or the sole result of state will, this realization of a right must be understood as part of a complex and dialectical social process, marked by political disputes, cultural resistance, and profound reconfigurations surrounding citizenship and legal equality. Based on a critical reading of Advisory Opinion OC-24/17, the role of the Inter-American Court of Human Rights, and the internal dynamics of the Costa Rican state, this work demonstrates how legal transformations occur in dialogue—and tension—with repertoires of mobilization, advocacy strategies, and identity-building processes promoted by diverse activist movements. This book offers the reader an analytical approach that articulates the theoretical elements, the socio-historical context, and the results of fieldwork, inviting an understanding of same-sex marriage not only as a legal achievement, but as a social transformation that continues to question the limits of democracy, heteronormativity, and contemporary policies of recognition.