Theophilus "Theo" Verster (born 14 January 1975) is a South African former swimmer, who specialised in butterfly and in individual medley events. He won three medals at the 1999 All-Africa Games, and later represented South Africa at the 2000 Summer Olympics. He also held an African record of 55.04 from the 2002 Telkom International Sprint Challenge that defeated Terence Parkin for a top finish and sliced off Brendon Dedekind's standard by 0.37 of a second. During his sporting career, Verster trained full-time under his personal coach Alisdair Hatfield.