 Rees was married in 1926 to Agatha Rosalie Innes, only daughter of Sir Charles Alexander Innes (1874–1959), a career India Civil Service officer and Governor of Burma from 1927–1932.They had one son, the Cabinet Minister Peter Wyford Innes Rees Rees (later Lord Rees), and one daughter.John Masters noted in one of his autobiographies (The Road Past Mandalay) that Pete Rees was an abstinent (he "spoke softly, never swore, never drank, did not smoke."