Sax is a surname. Notable people with the surname include:
- Adolphe Sax, the inventor of the saxophone
- Cole Sax, American director
- Dave Sax, Major League Baseball player
- Emil Sax, Austrian economist
- Geoffrey Sax, sometimes credited as Geoff Sax, film and television director
- George D. Sax, business entrepreneur, drive-in bank innovator
- Gyula Sax, Hungarian chess player
- Joseph Sax, American environmental law scholars
- Leonard Sax, American psychologist and physician.
- Karl Sax, American botanist and geneticist
- Marjan Sax (born 1947), Dutch feminist lesbian activist
- Sara Sax (1870–1949), American decorative ceramics artist
- Steve Sax, Major League Baseball player