Fassler or Fässler is a surname. Notable people with the surname include:
Hanspeter Fässler (born 1957), Swiss robotics pioneer and manager Hildegard Fässler (born 1951), Swiss politician Marcel Fässler (racing driver) (born 1976), Swiss racing driver Marcel Fässler (bobsleigh) (born 1959), Swiss bobsledder Margot Fassler American music historian