The University of Johannesburg (UJ) is a public university located in Johannesburg, South Africa. The University of Johannesburg came into existence on 1 January 2005 as the result of a merger between the Rand Afrikaans University (RAU), the Technikon Witwatersrand (TWR) and the Soweto and East Rand campuses of Vista University. Prior to the merger, the Daveyton and Soweto campuses of the former Vista University had been incorporated into RAU. As a result of the merger of Rand Afrikaans University (RAU), it is common for alumni to refer to the university as RAU. The vice-chancellor and principal of UJ is Professor Letlhokwa George Mpedi who took office on 1 January 2023. Between 2018 and 2022, UJ's vice-chancellor and principal was Tshilidzi Marwala.

Johannesburg is the most populous city in South Africa with 4,803,262 people, and is classified as a megacity; it is one of the 100 largest urban areas in the world. It is the provincial capital and largest city of Gauteng, which is the wealthiest province in South Africa. Johannesburg is the seat of the Constitutional Court, the highest court in South Africa. Most of the major South African companies and banks have their head offices in Johannesburg. The city is located within the mineral-rich Witwatersrand hills, the epicentre of the international-scale mineral, gold and (specifically) diamond trade.