Robert Arthur James Gascoyne-Cecil was born 27 August 1893 to James Edward Hubert Gascoyne-Cecil, 4th Marquess of Salisbury (1861-1947) and Cicely Alice Gore (1867-1955) and died 23 February 1972 of unspecified causes. He married Elizabeth Vere Cavendish (1897-1982) 1915 .
Children
| Name | Birth | Death | Joined with |
| Robert Edward Peter Gascoyne-Cecil, 6th Marquess of Salisbury (1916-2003) | 24 October 1916 | 11 July 2003 | Marjorie Olein Wyndham-Quin (1922) |
| Michael Charles James Gascoyne-Cecil (1918-1934) | |||
| Richard Hugh Gascoyne-Cecil (1924-1944) | |||
Siblings
| Name | Birth | Death | Joined with |
| Beatrice Edith Mildred Gascoyne-Cecil (1891-1980) | 10 August 1891 | 3 December 1980 | William George Arthur Ormsby-Gore, 4th Baron Harlech (1885-1964) |
| Mary Alice Gascoyne-Cecil (1895-1988) | 25 July 1895 Hatfield, Hertfordshire, England, United Kingdom | 24 December 1988 London, Greater London, England, United Kingdom | Edward William Spencer Cavendish, 10th Duke of Devonshire (1895-1950) |
| Robert Arthur James Gascoyne-Cecil, 5th Marquess of Salisbury (1893-1972) | 27 August 1893 | 23 February 1972 | Elizabeth Vere Cavendish (1897-1982) |
| Edward Christian David Gascoyne-Cecil (1902-1986) | |||