Albertus (Albert) Stephanus Geyser (10 February 1918 – 13 June 1985) was a South African cleric, scholar and anti-apartheid theologian. Geyser became an outcast in the white Afrikaner community because of his theological opposition to apartheid and to the Broederbond, the secret male Calvinist organisation that covertly steered South African politics during the apartheid era. He obtained master's and doctoral degrees cum laude, specializing in Greek and Latin. At the age of 27 he was appointed lecturer, and a year later, professor in the Theological Faculty of the Nederduitsch Hervormde Kerk at the University of Pretoria. Geyser contributed to the first annotated edition (1953–1958) of the Bible in Afrikaans, founded the Christian Institute, and was the first South African to be elected as