Simon John Manley CMG (born 18 September 1967) is a British diplomat, now the UK Permanent Representative to the WTO and UN in Geneva and previously Ambassador to Spain from October 2013 to August 2019.^[1]

Manley was educated at Montpelier Primary School, Latymer Upper School, Magdalen College Oxford and Yale University.^[2]

Manley joined the Foreign & Commonwealth Office (FCO) in 1990. Before his posting to Madrid, he served as Director Europe at the FCO (2011-2013), responsible for policy toward the EU. He has been posted to the UK's Mission to the United Nations in New York City (1993-1998), where he worked on Yugoslavia and UN reform, and has twice been seconded to the European Union: to the European Commission (2003) and to the Council of the EU (1998-2002).

In March 2020 Manley was appointed Director-General for COVID-19 at the Foreign & Commonwealth Office, leading and coordinating HMG's coronavirus rollout.^[3]

In June 2023 the World Trade Organisation's Trade and Gender Informal Working Group published its 2023-2024 plan. Manley and Clara Manuela da Luz Delgado Jesus were new, joining El Salvador's Ana Patricia Benedetti Zelaya, as co-chairs of the Working Group. They replaced Athaliah Lesiba Molokomme and Einar Gunnarsson.^[4]