| Honorific-Prefix: | Sir |
| Peter Westmacott | |
| Office: | British Ambassador to the United States |
| Term Start: | 28 January 2012 |
| Term End: | 28 January 2016 |
| Predecessor: | Sir Nigel Sheinwald |
| Successor: | Sir Kim Darroch |
| Primeminister: | David Cameron |
| Office1: | British Ambassador to France |
| Monarch1: | Elizabeth II |
| Term Start1: | 2007 |
| Term End1: | 2012 |
| Predecessor1: | Sir John Holmes |
| Successor1: | Sir Peter Ricketts |
| Primeminister1: | Gordon Brown David Cameron |
| Office2: | British Ambassador to Turkey |
| Term Start2: | 2002 |
| Term End2: | 2006 |
| Predecessor2: | Sir David Logan |
| Successor2: | Nick Baird |
| Monarch2: | Elizabeth II |
| Primeminister2: | Tony Blair |
| Birth Date: | 1950 12, df=y |
| Birth Place: | Edington, Somerset, England |
| Birthname: | Peter John Westmacott |
| Nationality: | British |
| Relations: | Herbert Westmacott (cousin) |
| Children: | 3 |
| Education: | Taunton School |
| Alma Mater: | New College, Oxford |
| Occupation: | Diplomat |
Sir Peter John Westmacott (born 23 December 1950) is a senior British diplomat, who was British Ambassador to Turkey, then Ambassador to France (2007 to 2011) and finally Ambassador to the United States from January 2012 to January 2016, succeeding Sir Nigel Sheinwald, a posting announced by the Prime Minister's Office on 24 June 2011.[1]
Westmacott joined the Foreign and Commonwealth Office in 1972, and his first overseas posting was as Second Secretary at Tehran, Iran, in 1974. In 1978, he was sent to the European Commission in Brussels, and from 1980 to 1984 he was in Paris. After a period in London he was in Ankara as Head of Chancery from 1987.
In 1990, he was Deputy Private Secretary to the Prince of Wales, and in 1993 was sent to Washington to serve as a Counsellor. Later postings included Director for the Americas in the Foreign and Commonwealth Office, and Deputy Under Secretary of State.
From 2002 to 2006, Westmacott was HM Ambassador to Turkey.[2]
Formerly HM Ambassador to France since 2007, Westmacott took over as HM Ambassador to the United States in January 2012. In 2015, Westmacott was paid a salary of between £170,000 and £174,999 by the Foreign Office, making him one of the 328 most highly paid people in the British public sector at that time.[3]
Westmacott was educated at Taunton School before going to New College, Oxford. In 1972, Westmacott married Angela Lugg, with whom he had two sons and a daughter. In 2001, he married an American, Susan Nemazee.[4]
Westmacott's father was Ian Westmacott, a reverend, and his mother was named Rosemary (née Watney).[4] His cousin, Captain Herbert Westmacott MC, was killed during a gunfight with the Provisional Irish Republican Army in Belfast in 1980.[5]
In March 1993 Westmacott was appointed a Lieutenant of the Royal Victorian Order. He was later appointed a Companion of the Order of St Michael and St George in the 2000 New Year Honours before being promoted to Knight Commander (KCMG) in the 2003 Birthday Honours and Knight Grand Cross (GCMG) in the 2016 Birthday Honours for services to diplomacy.