Tian Viljoen (born 10 April 1961, in Pretoria, South Africa), is a former professional tennis player from South Africa. He enjoyed most of his tennis success while playing doubles. During his career he finished runner-up in doubles at three events. He achieved a career-high doubles ranking of World No. 49 in 1983.
Doubles runner-ups (3)
|Outcome||No.||Date||Tournament||Surface||Partner||Opponents in the final||Score in the final|
|Runner-up||1.||1982||Munich, Germany||Clay||Danie Visser|| Chip Hooper
|Runner-up||2.||1983||La Quinta, U.S.||Hard||Danie Visser|| Brian Gottfried
|Runner-up||3.||1983||Palermo, Italy||Clay||Danie Visser|| Pablo Arraya
José Luis Clerc
|6–1, 4–6, 4–6|