John Mason Kemper (September 1, 1912 – December 4, 1971) was a military historian and the 11th Headmaster of Phillips Academy Andover, serving for 23 years, from 1948 to 1971.

In the Army, Kemper had led the service's World War II historical program branch; the program today is now the United States Army Center of Military History.

[4][5][6][7] In 1951, Kemper convinced the Lawrenceville School and Phillips Exeter Academy to join in what became the Advanced Placement program offering college level courses to high school students.

Kemper also sought to dispel the view that private schools like Andover were "training grounds for snobs", and worked to diversify the student body.

He soon after died of cancer in December 1971, and is buried at the Phillips Academy Cemetery.