Threlfall is a surname. Notable people with the surname include:
David Threlfall (born 1953), English actor Dick Threlfall (1916–1994), English footballer Edward Threlfall, English footballer in the 1900s George Threlfall (engineer) (1819–1897), English-born Australian engineer and entrepreneur George Threlfall (footballer) (1899–1988), Australian rules footballer Jeanette Threlfall (1821–1880), English hymnwriter, religious poet Mary Threlfall (1910–1996), Australian nurse Philip Threlfall (born 1967), English cricketer Sir Richard Threlfall (1861–1932), English chemist and engineer in Australia Robbie Threlfall (born 1988), English footballer T. R. Threlfall (1852–after 1932), English trade unionist and politician Wilf Threlfall (1906–1988), English footballer William Threlfall (1888–1949), German mathematician