Margaret Constance "Maisie" Williams (born 15 April 1997) is an English actress who made her acting debut in 2011 as Arya Stark, a lead character in the HBO epic medieval fantasy drama series Game of Thrones (2011–2019). Williams garnered critical praise and accolades for her work on the show, receiving two nominations for the Primetime Emmy Award for Outstanding Supporting Actress in a Drama Series and global recognition. Williams' other television appearances include guest starring on the BBC science fiction series Doctor Who (2015), the British docudrama television film Cyberbully (2015), the British science-fiction teen thriller film iBoy (2017) and the comedy action drama series Two Weeks to Live (2020). Williams also voiced Cammie MacCloud in the American animated web series Gen:Lock (2019–present).

In 2014, she starred in her first feature film, the coming-of-age mystery drama The Falling, for which she received critical acclaim and awards recognition. She had co-starring roles in films such as the romantic period-drama film Mary Shelley (2017), the animated prehistorical sports comedy film Early Man (2018), and the romantic comedy-drama film Then Came You (2018). In 2020 she starred in the superhero horror film The New Mutants and the psychological thriller The Owners. In 2018, she made her stage debut in Lauren Gunderson's play I and You at the Hampstead Theatre in London, to positive critical reviews.