Lady Dorothy Evelyn Macmillan, GBE (née Cavendish; 28 July 1900 – 21 May 1966) was a daughter of Victor Cavendish, 9th Duke of Devonshire and Evelyn Cavendish, Duchess of Devonshire and the wife of the British Prime Minister Harold Macmillan.

Family life

She spent her first eight years at Holker Hall, Lancashire, and Lismore Castle, Ireland. She became known as Lady Dorothy from the age of eight, when her father succeeded to the dukedom, and the family moved into Chatsworth House, Derbyshire, and the other ducal estates. She received lessons in French, German, riding and golf. From the age of sixteen she lived with the family at Rideau Hall, Ottawa, where her father served as Governor General of Canada.

In 1920 she married the publisher and Conservative politician Harold Macmillan, who had been on her father's staff in Canada. Their lavish wedding, on 21 April at St. Margaret's, Westminster, was attended by royalty, aristocracy and leading literary figures, and was hailed as the social event of the London season.

Lady Dorothy was a dutiful political wife and the couple remained together (despite her long-lasting affair with the bisexual Conservative politician Robert Boothby) until her death from a heart attack at the Macmillan family estate at Birch Grove, East Sussex, in 1966. Her husband, who was created 1st Earl of Stockton in 1984, outlived her by 20 years.

She and Harold had four children:

• Maurice Macmillan, Viscount Macmillan of Ovenden (1921–1984), a Conservative politician and publisher. Married The Honourable Katharine Ormsby-Gore, a daughter of the 4th Baron Harlech. His father outlived him by nearly three years.
• Lady Caroline Macmillan (1923–2016). Married Julian Faber; five children. Their last surviving child following the death of Lady Catherine Macmillan in 1991.
• Lady Catherine Macmillan (1926–1991). Married Julian Amery, later Baron Amery of Lustleigh, a Conservative politician; four children.
• Sarah Macmillan (1930–1970). She had an unhappy life, which was blighted by a drinking problem, and died aged only 40, her father outliving her by 16 years.