Michael William McCrum CBE (23 May 1924 – 16 February 2005) was an English academic and ancient historian who served as Vice-Chancellor of the University of Cambridge, Master of Corpus Christi College, Cambridge, and Head Master of Tonbridge School and Eton College.

McCrum was born at Alverstoke in Hampshire, England. The son of a naval Captain, he grew up at naval bases where his father was stationed. He was educated at Horris Hill School, Newbury and Sherborne School before Second World War service as an able seaman and then sub-lieutenant in the Royal Navy. He then won a scholarship to study classics at Corpus Christi College, Cambridge. He graduated in 1948 with a Double First.

After graduation, McCrum became a master at Rugby School. He married the daughter of the headmaster, Sir Arthur fforde, in 1952. McCrum was appointed Fellow of Corpus Christi in 1950 and was an (innovative) Tutor there under the Master, Sir George Thomson, and was also Director of Classical Studies.

McCrum left Cambridge in 1962 to become headmaster of Tonbridge School, where he earned a good reputation and transformed the school, emphasising academic standards and implementing sweeping reforms, including the abolition of the old traditions of fagging and caning of junior boys by "praepostors" (senior boys). He also made the Cadet Corps voluntary. The Tonbridgian (the school magazine) wrote in 1967 that "Never have there been so many changes in so short a time".

Through a clever strategy, he ensured that straw boater hats ("barges") remained, despite a clear majority in a poll among the boys that favored abolishing them. His imposing stature and remarkable ability to memorize the names and faces of every boy (and master) in the school within the first week of the autumn term earned him respect and command. He later described part of his task at Tonbridge as having been "the reduction of stupid anachronisms" and "giving boys more liberties, provided they do not take them"; corporal punishment, he said, was "often the lesser of two evils".

While at Tonbridge, McCrum was an early supporter of the idea of education vouchers, and he opposed Labour Party proposals for school reform.

He criticised the reduction of the age of majority and the voting age to 18, saying that while they might be outwardly more mature than formerly, 18-year-olds "were still searching for guidance and authority" and "were less aware than formerly of the framework of tradition and the concept of the family community" under the increasing influence of the press and media.

In 1970, he became Head Master of Eton College, ostensibly a more prestigious position but perhaps one that allowed less initiative or authority than at Tonbridge. He raised standards at Eton after the era of Anthony Chenevix-Trench, whose weaknesses differentiated him from the self-disciplined McCrum. The curriculum was modernised and academic standards improved. Just before leaving Eton he oversaw the final abolition of fagging, as he had at Tonbridge earlier.