Theunissen is a small town situated in the Free State province of South Africa. Geographically, it is located along the R30 road, approximately 95 kilometers northeast of Bloemfontein and about 45 kilometers south of Welkom.
The town was founded by Boer War Commandant Helgaardt Theunissen. It is notable for hosting the Theunissen Wine Farm, which is the only wine estate located within the Free State province.