Peter Alan Sweet (1921–2005) was an English astronomer. He was Regius Professor of Astronomy at the University of Glasgow from 1959 until his retirement in 1982. He was also Dean of the Faculty of Science 1973–1975. Under Sweet's stewardship, the Department of Astronomy grew from 3 to 17 permanent staff. Sweet undertook the building of a new University Observatory located at Acre Road, Glasgow which opened in 1967. The department offices were moved to the top floor of the then new Mathematics Building in University Gardens, within the main University campus.