He married, firstly, Marjorie Ellinor Trotter, the granddaughter of John Hamilton, 1st Baron Hamilton of Dalzell, on 10 June 1920 and they were divorced in 1941. They had three children:
Richard Archibald Fortescue, 7th Earl Fortescue he married Penelope Henderson on 24 October 1949. They have two children, five grandchildren and one great-grandson. He remarried Margaret Stratton on 3 March 1961 and they were divorced in 1987. They have two daughters and two grandsons. He remarried, again, Carolyn Hill on 5 January 1989.
*Charles Hugh Richard Fortescue, 8th Earl Fortescue he married Julia Sowrey on 12 December 1974. They have three daughters and one grandson:
**Lady Alice Penelope Fortescue
**Lady Kate Eleanor Fortescue she married Oliver Henry Bonas. They have one son:
***Ossie Charles Bonas
**Lady Lucy Beatrice Fortescue
*Lady Celia Ann Fortescue+ she married David Adams in 1988. They have two children:
*Lady Laura Margaret Fortescue+ she married Simon Jamieson on 1 July 1995. They have two sons:
**Jerry Jocelyn Jamieson
**Hugh Archibald Jamieson
*Lady Sarah Jane Fortescue she married Francis David Sherston Chapman on 19 December 1995.
The Honorable Martin Fortescue he married Prudence Rowley on 23 April 1954. They have four children and eight grandchildren. He remarried Caroline Lofte on 18 November 1994.
*John Andrew Francis Fortescue he married Phoebe Burridge in 1990. They have three children:
**Thomas Henry Horatio Fortescue
**Hugh Augustus Francis Fortescue
**Ophelia Marion Louisa Fortescue
*Katharine Fortescue she married Robert Whitaker, son of Evald Mattievich Whitaker, on 9 September 1995.
*Georgina Elizabeth Fortescue she married Nicholas Armour on 31 July 1982. They have two daughters:
**Emily Frances Armour
**Sophie Elizabeth Armour
*Anthony William Fortescue he married Emma Lambert in 1992. They have three children:
**William George Fortescue
**Amelia Prudence Fortescue
**Lucy Emma Fortescue
Lady Bridget Ellinor Fortescue she married Wing Commander Gordon Sinclair on 25 November 1952. They have four children and eleven grandchildren:
*Alan Gordon William Sinclair he married Fiona B. MacEwan in 1983. They have three sons:
**Thomas Sinclair
**Archie Sinclair
**Geordie Sinclair
*Caroline Fiona Sinclair she married Julian Raymond Eric Smith, son of Jeremy Fox Eric Smith and Julia Mary Rona Burrell, on 8 May 1982. They have three children:
**Oliver George Eric Smith
**Lucy Alexandra Smith
**Henry Thomas Eric Smith
*Joanna Rosalind Sinclair she married Mark P. R. Rimell in 1992. They have two children:
**Benjamin Charles Philip Rimell
**Amelia Sophie Rimell
*Robert Alister Sinclair he married Rebecca Power. They have three children:
The Honorable Seymour Henry Fortescue he married Julia Pilcher in 1966 and they were divorced in 1990. They have two children and six grandchildren. He remarried Jennifer Simon on 23 August 1990. They have one daughter.
*Marissa Clara Fortescue she married Maximilian, 7th Prince of Bentheim-Tecklenburg-Rheda, on 30 September 2000. They have four children:
**Moritz Friedrich Carl, Hereditary Prince of Bentheim-Tecklenburg-Rheda