Thirlwall is a surname. Notable people with the surname include:
- Anthony Thirlwall (born 1941), Professor of Applied Economics at the University of Kent
- Thirlwall's Law, a law of economics
- Connop Thirlwall (1797–1875), English clergyman and historian, Bishop of Saint David's
- Thirlwall Prize, awarded at Cambridge University
- Jade Thirlwall (born 1992), an English singer
- William Thirlwall, English MP