Sophie Belinda Turner was born in Northampton, England on 21 February 1996, the daughter of Sally, a nursery school teacher, and Andrew, who works for a pallet distribution company. She moved to Chesterton, Warwickshire when she was 2 years old. She attended Warwick Prep School until she was 11, and later attended the independent The King’s High School for Girls. Turner has been a member of the Playbox Theatre Company since she was 3 years old. She has two older brothers. Her twin sister died before birth.
She grew up in a large Edwardian house, near Leamington Spa, saying, “My childhood was pretty fun. We had pigsties, barns and a paddock, and used to muck around in the mud.” Turner had a tutor on the set of Game of Thrones until the age of 16. She achieved five GCSE A-grades and four Bs, including a B in Drama
She made her acting debut as Sansa Stark on the HBO epic fantasy television series Game of Thrones (2011–2019), for which she received a Primetime Emmy Award nomination for the Outstanding Supporting Actress in a Drama Series in 2019.
Turner appeared in the television film The Thirteenth Tale (2013) and made her feature film debut in Another Me (2013). She appeared in the action comedy Barely Lethal (2015) and portrayed a young Jean Grey / Phoenix in the X-Men film series (2016–2019).