Alexandra, informally abbreviated to Alex, is a township in the Gauteng province of South Africa. It forms part of the City of Johannesburg Metropolitan Municipality and is located next to the wealthy suburb of Sandton. Alexandra is bounded by Wynberg on the west, Marlboro and Kelvin on the north, Kew, Lombardy West and Lombardy East on the south. Alexandra is one of the poorest urban areas in the country. Alexandra is situated on the banks of the Jukskei River. In addition to its original, reasonably well-built houses, it also has a large number of informal dwellings or "shacks" called imikhukhu.

In South Africa, the terms township and location usually refer to the often underdeveloped racially segregated urban areas that, from the late 19th century until the end of apartheid, were reserved for non-whites, namely Black Africans, Coloureds and Indians. Townships were usually built on the periphery of towns and cities. The term township also has a distinct legal meaning in South Africa's system of land title, which carries no racial connotations.