The processes that led to legal recognition of same-sex unions in Brazil and in the United States followed clearly different paths. Instead of pursuing legalization of same-sex marriage as a primary goal of their political agenda like their American counterparts, Brazilian gay and lesbian couples first sought access to the institutions that regulate domestic cohabitation. The early jurisprudential characterization of the family as an institution independent from marriage encouraged them to center litigation on the possibility of classifying same-sex couples as family entities. Gay and lesbian couples claimed in a series of lawsuits that they build a form of union that provides them with the same benefits that heterosexual individuals obtain from their relationships, a reason why the Brazilian legal system should not deny them equal legal treatment. Many courts acknowledged the validity of their claims in several decisions that gradually extended spousal rights to same-sex couples, a process that prepared the ground for the recent Supreme Court decision that legalized same-sex unions in the country. This article explains the development of the Brazilian same-sex union litigation and adjudication as a story about the convergence of two important jurisprudential developments: the long national tradition of giving legal protection to domestic cohabitants, and the emergence of a strand of decisions that understands equality as a constitutional principle that aims to eradicate structural forms of inequalities. By adopting an incremental approach to gay marriage litigation, Brazilian same-sex couples have achieved effective legal protection. The Brazilian case serves as an interesting point of comparison for same-sex marriage advocates elsewhere in the world, since this gradual approach tends to be dismissed as a litigation strategy that could deliver equal legal treatment.