| Honorific-Prefix: | The Right Honourable |
| The Earl of Balfour | |
| Office14: | Member of the House of Lords Lord Temporal |
| Term Start14: | 14 January 1945 |
| Term End14: | 28 November 1968 as a hereditary peer |
| Predecessor14: | The 2nd Earl of Balfour |
| Successor14: | The 4th Earl of Balfour |
| Birth Date: | 31 December 1902 |
| Birth Place: | Fishers Hill House, Hook Heath, Woking |
| Alma Mater: | Trinity College, Cambridge |
| Children: | 4, including Gerald Balfour, 4th Earl of Balfour |
| Parents: | Gerald Balfour, 2nd Earl of Balfour Lady Betty Bulwer-Lytton |
Robert Arthur Lytton Balfour, 3rd Earl of Balfour (31 December 1902 – 28 November 1968), styled Viscount Traprain between 1930 and 1945, was a Scottish peer.
Balfour was the son of Gerald Balfour, a Member of Parliament, and his wife Lady Elizabeth Balfour (née Bulwer-Lytton), a daughter of the 1st Earl of Lytton. He was the nephew of Prime Minister Arthur Balfour, and his father succeeded as Earl of Balfour in 1930. Robert was born on 31 December 1902 at his parent′s residence Fishers Hill House, Hook Heath, Woking,[1] and was educated at Eton and Trinity College, Cambridge. He rose to the rank of Lieutenant in the service of the Royal Naval Reserve and fought in the Second World War.
On 12 February 1925, he married Jean Lily West Roundel Cooke-Yarborough (1900–1981). They had four children:
From 1952 to 1954, he chaired the Royal Commission on Scottish Affairs, which as a result is also referred to as the Balfour Commission.