Ornstein is a surname of Jewish origin. Notable people with the surname include:
- Axel Ornstein (b. 1952), Swedish chess master
- Donald Samuel Ornstein (b. 1934), American mathematician
- Jonathan G. Ornstein, CEO of Mesa Air Group, Inc.
- Leo Ornstein (1895–2002), Russian-American composer
- Leonard Salomon Ornstein (1880–1941), Dutch physicist known for the Ornstein–Zernike equation and the Ornstein–Uhlenbeck process
- Michael Marisi Ornstein (b. 1963), American actor
- Norman J. Ornstein (born 1948), American political scientist
- Robert Ornstein (b. 1942), American psychologist
- Severo Ornstein (born 1930), American computer scientist and son of Leo Ornstein
In video games
edit- Dragon Slayer Ornstein, an enemy boss in the game Dark Souls.