Sarah Elizabeth Arwen MacDonald[1] (born 22 November 1968) is a Canadian-born organist, conductor, and composer, living in the United Kingdom, and currently holds the positions of Fellow and Director of Music at Selwyn College, Cambridge,[2] and Director of the girl choristers at Ely Cathedral.

MacDonald came to the United Kingdom from Canada in 1992 as organ scholar of Robinson College, Cambridge, after studying piano, organ, and conducting at The Royal Conservatory of Music's Glenn Gould School in Toronto with Leon Fleisher, Marek Jablonski,[4] and John Tuttle.

[5] MacDonald has played numerous recitals and conducted choirs throughout the UK, North America, the Middle East, New Zealand, and much of mainland Europe.

For its first 10 years, she was a regular director of the Girl Chorister Course at St Thomas' Church Fifth Avenue, in New York City,[7] and is a guest conductor of international RSCM residential courses (Charlotte NC 2016, Rhode Island 2017, Pacific Northwest 2018, Australia 2020).

In 2023 she was appointed University Organist at Cambridge, the first woman to hold this ceremonial role which dates back to 1670.