St Mary's School, Calne

St Mary's School is a private day and boarding school in Calne, Wiltshire, England, for girls aged 11 to 18. The school is a registered charity.

In 2023, the school's A Level results ranked third in the UK and joint second in the south-west of England.

St Mary's was founded in 1873 by Canon John Duncan, Vicar of Calne, who worked for over thirty years to establish it as an 'outstanding' girls' school.

Research for her 2006 novel Wicked! led author Jilly Cooper to interview former pupils.

In the 2017 ISI report, the school received a double 'excellent' – the highest possible grade.^{[citation needed]}

In figures published in January 2017 by the Department for Education (DfE) regarding 2016 A Level results, St Mary's Calne got the top score for its 'value added' – that is, how much progress students who studied A Levels made between the end of Key Stage 4 and the end of their A Level studies, compared to similar students across England. St Mary's Calne scored 'well above the national average', to be in the top 4% of schools in England with this value added score.

The school is divided into five companies, named after bishops with local connections: Edmund Rich, Grossetête, Moberly, Osmund, and Poore. Each girl remains in the same company throughout her time at the school. The companies are similar to houses in other independent schools, except that they have nothing to do with the house a girl sleeps in. The companies compete in sport, drama, music, and other activities such as quizzes, public speaking, and maths challenges.

There are seven boarding houses, for each year group from LIV to UVI. The houses are School House, St. Prisca's, St. Cecilia's, Gibbins, Joyce Walters, Florence Dyas, and Helen Wright. The newest house is Florence Dyas, the LVI house, which was opened in September 2014.