Sinfield is a surname. Notable people with the surname include:
Alan Sinfield (1941–2017), British academic Ian Sinfield (athlete) (1934–2010), Australian runner Ian Sinfield (born 1977), Scottish rugby player Kevin Sinfield (born 1980), English rugby player Melissa Sinfield (born 1977), Australian basketball player Peter Sinfield (1943–2024), English songwriter Reg Sinfield (1900–1988), English cricketer