 He was married in 1903 to Lady Sybil Myra Caroline Primrose (1879–1955), eldest daughter of Archibald Primrose, 5th Earl of Rosebery, who had served as British Prime Minister from 1894 to 1895.They had one son, Charles Robert Archibald Grant (1903-1972), who married Pamela Wellesley (1912-1987), a granddaughter of the 4th Duke of Wellington.Grant died at his wife's property, The Durdans, Epsom, Surrey, aged 73, in November 1950, and was buried in the family grave at Balmacaan, Glen Urquhart, Inverness-shire, Scotland.