John Bernard Duff (July 1, 1931 - October 1, 2013) was an American historian born in South Orange, New Jersey, on July 1, 1931, to John Bernard Duff, Sr. and Mary Cunningham Duff. He was the oldest of four brothers: Thomas, Joseph and Peter Duff. He graduated from Our Lady of the Valley High School in 1949. In 1955, he married Helen Dorothy Mezzanotti, to whom he was married for 33 years. In 1976, he became the first president of the new University of Lowell, in Lowell, Massachusetts, which would later become the University of Massachusetts Lowell.