Wirz is a Swiss surname. Notable people with the surname include:
George Otto Wirz, 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, Swiss field handball player
Susi Wirz, Swiss figure skater
Valentin Wirz, Swiss ice hockey player