| Honorific-Prefix: | The Right Honourable |
| The Lady Tweedsmuir | |
| Birth Name: | Susan Charlotte Grosvenor |
| Birth Date: | 20 April 1882[1] |
| Birth Place: | London, England |
| Death Date: | 22 March 1977 (aged 94) |
| Death Place: | Burford, Oxfordshire, England |
| Nationality: | British |
| Genre: | Fiction, History, Biography |
| Spouse: | John Buchan |
| Children: | Alice, John, William, Alastair |
| Parents: | Norman de L'Aigle Grosvenor Caroline Stuart-Wortley |
Susan Charlotte Buchan, Baroness Tweedsmuir DStJ (née Grosvenor; 20 April 1882 – 22 March 1977) was a British writer and the wife of author John Buchan. Between 1935 and 1940 she was viceregal consort of Canada while her husband was the governor general.[2] She was also the author of several novels, children's books, and biographies, some of which were published under the name Susan Tweedsmuir.[3]
Susan was born in Mayfair, London.[4] She was a daughter of Norman de L'Aigle Grosvenor (son of the first Lord Ebury) and his wife Caroline Susan Theodora Stuart-Wortley (a granddaughter of the first Lord Wharncliffe), and a cousin of the Dukes of Westminster. She married John Buchan on 15 July 1907, and became the Baroness Tweedsmuir (known as Lady Tweedsmuir) when he was created Baron Tweedsmuir in 1935. The Buchans had four children, Alice, John, William, and Alastair, two of whom would spend most of their lives in Canada.
She was a childhood friend of Virginia Stephen (later Virginia Woolf), and they remained friendly, although not always close, in adult life. The Hogarth Press, run by Leonard and Virginia Woolf, published a work of Lady Tweedsmuir's in 1935 and she was the recipient of one of the last letters Virginia Woolf wrote.[5]
Her time as Vicereine of Canada is remembered for her energetic relief work. Her library project of gathering books in Eastern Canada for impoverished western communities and sending train carloads of them west was the foundation for many public libraries across the prairies.[6]
Her interest in literary education influenced the establishment of the Governor General's Awards, for many years Canada's primary literary awards, and the library at Rideau Hall.[7] Following her husband's death she returned to Britain, where she wrote several more novels, a series of memoirs, and a biography of her husband.
She died at Burford, near Oxford, on 22 March 1977 aged 94 and was buried beside her husband in the churchyard at Elsfield.[8]