Lady Antonia Margaret Caroline Fraser, CH, DBE, FRSL (née Pakenham; born 27 August 1932) is a British author of history, novels, biographies and detective fiction.

Before his own conversion in his thirties following a nervous breakdown in the Army, as she explains: "My father was Protestant Church of Ireland, and my mother was Unitarian up to the age of 20 when she abandoned it.

[2][11] Her first major work, published by Weidenfeld & Nicolson, was Mary, Queen of Scots (1969), which was followed by several other biographies, including Cromwell, Our Chief of Men (1973).

[12] The book was cited as an influence on the 2003 BBC/A&E mini-series, Charles II: The Power & the Passion, in a featurette on the DVD, by Rufus Sewell who played the title character.

[15] Fraser served as editor for many monarchical biographies, including those featured in the Kings and Queens of England and Royal History of England series, and, in 1996, she also published a book entitled The Gunpowder Plot: Terror and Faith in 1605, which won both the St. Louis Literary Award and the Crime Writers' Association (CWA) Non-Fiction Gold Dagger.

My Life with Harold Pinter was published in January 2010 and she read a shortened version as BBC Radio Four's Book of the Week that month.

[18] From 1956 until their divorce in 1977, she was married to Sir Hugh Fraser (1918–1984), a descendant of Scottish aristocracy 14 years her senior and a Roman Catholic Conservative Unionist MP in the House of Commons (sitting for Stafford), who was a friend of the American Kennedy family.

[4] On 22 October 1975, Hugh and Antonia Fraser, together with Caroline Kennedy, who was visiting them at their Holland Park home, in Kensington, west London, were almost blown up by an IRA car bomb placed under the wheels of his Jaguar, which had been triggered to go off at 9 am when he left the house; the bomb exploded, killing the cancer researcher Gordon Hamilton Fairley.

[2][8] Merchant spoke about her distress publicly to the press, which quoted her cutting remarks about her rival, but she resisted divorcing Pinter.

Lady Antonia Fraser's uncatalogued papers (relating to her "Early Writing", "Fiction", and "Non-Fiction") are on loan at the British Library.