Wirz is a Swiss surname. Notable people with the surname include:
- George Otto Wirz (1929–2010), American Roman Catholic bishop
- Henry Wirz, American officer of the Confederate States Army
- Johann Jakob Wirz, Swiss Theosophist prophet
- Rodolfo Wirz, Uruguayan Roman Catholic bishop
- Rudolf Wirz (1918–?), Swiss field handball player
- Susi Wirz (born 1931), Swiss figure skater
- Valentin Wirz (born 1981), Swiss ice hockey player