Karel Třešňák (born 21 February 1949 in Karlovy Vary)^[1] is a former Czechoslovak slalom canoeist who competed in the 1970s. He won seven medals at the ICF Canoe Slalom World Championships with two golds (C-1 team: 1973, 1975) a silver (C-1: 1973) and four bronzes (C-1: 1977; C-1 team: 1971, 1977, 1979).

Třešňák also finished seventh in the C-1 event at the 1972 Summer Olympics in Munich.

• ICF medalists for Olympic and World Championships – Part 2: rest of flatwater (now sprint) and remaining canoeing disciplines: 1936–2007 at WebCite (archived November 9, 2009)