Sasha Siem is a British-Norwegian singer-songwriter and composer.

Sasha studied music and poetry at Cambridge University and Harvard University. By her early twenties she had written music for the London Symphony Orchestra, The Royal Opera House, Rambert Dance Company, Opera North, The Aldeburgh Festival, Caius Choir Cambridge, Le Nouvel Ensemble Moderne, The London Sinfonietta, and the London Philharmonic Orchestra . In 2010, she became one of the youngest people to win a British Composer Award . She has also been awarded the Arthur Bliss Prize and the Royal Philharmonic Society Composition Prize.