Sarah Lianne Ayton Dempsey OBE (born 9 April 1980 in Ashford, Surrey) is an English professional sailor.
She won a gold medal in the Yngling sailing class in the 2004 Summer Olympics in Athens, together with Shirley Robertson and Sarah Webb, and another gold medal in the Yngling sailing class in the 2008 Summer Olympics in Beijing, together with Pippa Wilson and Sarah Webb.
Already a Member of the Order of the British Empire (MBE), Ayton was appointed Officer of the Order of the British Empire (OBE) in the 2009 New Year Honours. She married windsurfer Nick Dempsey in October 2008. Together, they have a son, Thomas-Flynn, who was born on the 28th June 2009.
Ayton is a patron of Meningitis UK. Ayton battled with meningococcal meningitis and septicaemia in 1995, when she was aged 14.