Rio de Janeiro, Brazil’s capital from 1763 to 1960, went through significant changes in the late nineteenth and early twentieth centuries, as the country abolished slavery in 1888 and transitioned from an empire to a republic in 1889. Tens of thousands of former slaves poured into the capital. Equal numbers of European immigrants sought out Rio as a site for new economic opportunities. The new federal government invested in both urban removal and urban renewal, pushing poor and working-class people out of the downtown area and into surrounding hillsides and distant suburbs in an effort to improve public health and remake the centre in the image of a European capital. Female prostitution was corralled into a specific zone, and the police closely monitored same-sex public sociability and sexuality. Annual Carnival celebrations became a unique moment in the city’s yearly calendar where residents could play with the rigid social restrictions placed on gender and sexuality. This chapter traces the changes that took place in gender performance and sexual behavior over the course of the twentieth century, as women and queer men expanded their access to public space and Rio’s Carnival became an international site for audacious expressions of licentiousness and eroticism.