Ann Katharine Swynford Lambton PhD FBA OBE (8 February 1912 – 19 July 2008), usually known as A.K.S. Lambton or "Nancy" Lambton, was a British historian and expert on medieval and early modern Persian history, Persian language, Islamic political theory, and Persian social organisation. She was an acknowledged authority on land tenure and reform in Iran, Seljuq, Mongol, Safavid and Qajar administration and institutions, and local and tribal histories.
From 1939–45, she was Press attaché of the British Legation to Tehran and then Professor of Persian at SOAS from 1953–79 succeeding Arthur Arberry as holder of that chair. In 1942, she was awarded the OBE and, later, honorary DLitt degrees from the University of Durham and the University of Cambridge. She was also an honorary fellow of New Hall, Cambridge, SOAS and the University of London. She wrote several books on subjects ranging from Persian grammar and vocabulary to Qajar land reform. Ann Lambton played a role in overthrowing the democratically elected government of Mohammed Mossadegh. After the decision to nationalize Iran's oil interests in 1951, she advised the British government to undermine the authority of Mossadegh's regime. She proposed that Oxford University professor R. C. Zaehner should go to Iran and begin covert operations. In 1953, with the help of the CIA, the regime of Mossadegh was overthrown and the Shah was restored to the throne.
As Professor Emeritus of the Diocese of Newcastle and Chairman of the Iran Diocesan Association, Lambton served on the Middle East Committee and advised Archbishops on inter-faith matters. She delivered Lent lectures biannually to clergy and laity for many years. She was later awarded the Cross of St Augustine in 2004 by the Archbishop of Canterbury in acknowledgement of her work and commitment to Christianity and the Church of England. She was an honorary Life Member of the Middle East Studies Association of North America. At the University of Durham, the Centre of Iranian Studies has instituted an annual Prof. A. K. S. Lambton honorary lectureship. Prof. Lambton delivered the inaugural lecture in this series in 2001. Prof. Lambton was also a lay reader and took services at the church of St Gregory the Great, Kirknewton, and St Mary & St Michael's Church, Doddington, Northumberland.
- Arbuthnott, H.; Professor Ann Lambton: Persian scholar, Obituary, The Times, 23 July 2008 .
- McLachlan, K. S.; Professor AKS Lambton, Obituary, Telegraph, 8 August 2008.
- Morgan, David; Ann Lambton, The Guardian, 15 August 2008,
- Waghmar, Burzine K.; Professor Ann Lambton: Persianist unrivalled in the breadth of her scholarship whose association with Soas was long and illustrious, Obituary, The Independent, 1 August 2008.
- Funeral of SOAS Persian Scholar Professor Ann Lambton, SOAS, 22 July 2008.
- Fariba Amini, When "great" scholars play a deadly role, Payvand, 11 February 2008.
- Farangis Mohebbi, Dr Yarshater: Lambton predicted the Iranian Revolution, in Persian, Radio Zamaneh, 13 August 2008, Audio.