Sydney was the original site of British settlement in Australia and its largest city in the twentieth century. With a reputation for hedonism, Sydney’s identity became entangled, to a marked extent, in its sexual cultures. The preoccupation with whiteness ensured that attitudes to birth control were closely related to settler racial aspirations. State regulation of sex work and female sexuality was also connected to concerns about preserving racial vigour, but it helped to secure a powerful role for organized crime and police corruption in the city’s sex industry. Key Sydney sex radicals and reformers took their place in British imperial and, to an increasing extent, global networks. Gay (or ‘camp’) male subcultures emerged in the middle decades of the century and, after a period of greater freedom during the Second World War, attracted repression in the 1950s. Lesbian subcultures emerged more slowly, but were discernible by the 1960s. At the same time as the contraceptive pill was transforming heterosexual relations, Sydney emerged as Australia’s major centre of gay life as well as a place of notable ethnic diversity and sexual variety. By the end of the century the city’s identity was bound more tightly than ever to its sexual cultures.