Marthinus Wilhelminus S. Theunissen (13 May 1911 – July 1983) was a South African athlete who competed in the 1936 Summer Olympics. He was born in Standerton.
In 1936 he was eliminated in the semi-finals of the 200 metres event and in the quarter-finals of the 100 metres competition. He was also a member of the South African team which was eliminated in the first round of the 4x100 metre relay contest. At the 1934 Empire Games he won the silver medal in the 100 yards event as well as in the 220 yards competition.
Theunissen is a small town that has the only wine estate, the Theunissen Wine Farm, in the Free State province of South Africa. It was founded by Boer War Commandant Helgaardt Theunissen. Theunissen has a small community (mostly farmers and miners) which supports the local businesses.
The founding of Theunissen and its history goes hand in hand with the development of the railway system in the Orange Free State (OFS). When gold was discovered in the Witwatersrand, railways to the new gold fields were a necessity. During this period there were no railways in the OFS and the Transvaal. The nearest railway lines were Kimberley and Pietermaritzburg. Connecting to the coastal ports from the Witwatersrand was vital. A race started from the Natal and Cape coastal ports to connect with the gold fields. In 1887 the Cape government received a concession from the OFS government to build a railway line through the OFS. This railway line was completed in sections which were opened on the following dates:
Theunissen is a Dutch patronymic surname meaning "son of Theunis", a nickname for Anthonius. People with this surname include: