St Mary's College Wellington is situated in the suburb of Thorndon in Wellington, New Zealand. The school is a state-integrated all-girls Catholic secondary school for years 9âÂÂ13.
The school, which is one of the oldest existing schools in New Zealand, was founded in 1850 by Philippe Viard, first Bishop of Wellington and staffed from 1861 by a small group of religious sisters, the "Sisters of Mary", established by Viard. Part of the land on which the school is situated was donated by Lord Petre, the 11th Baron Petre (1793âÂÂ1850), who was a director of the New Zealand Company and whose family seat Thorndon Hall in Essex was an important centre of Catholic Recusancy from the time of Queen Elizabeth I. The area of Central Wellington in which the school is located is also named after Thorndon. Another part of the site was given by Sir George Grey, Governor of New Zealand out of public funds. In 1861 the school was taken over by the Sisters of Mercy (absorbing the earlier group) when they arrived in Wellington in that year. To begin with, the school was co-educational (boys and girls) and had a boarding facility attached. Nowadays the boarding facility is gone, and it is a single sex girls' school.
As a state-integrated school, the proprietors of St Mary's College charge compulsory attendance dues to cover capital costs. For the 2025 school year, the attendance dues payable is $1,147 per year per student.
As of , St Mary's College has a roll of students, of which (%) identify as MÃÂori.
As of , the school has an Equity Index of , placing it amongst schools whose students have socioeconomic barriers to achievement (roughly equivalent to deciles 8 and 9 under the former socio-economic decile system).
While most traces of the original buildings on the site have disappeared, buildings dating from the twentieth century as the latest, including the "Gabriel Block" which is now used as the school hall. The other two main blocks are "Carlow" and "McAuley". McAuley is named after Sister Catherine McAuley, who used her inherited fortune to found the Sisters of Mercy in Dublin, Ireland.
The school remains in the ownership of the Sisters of Mercy and describes itself as a "Mercy School". The Gabriel Hall and St Joseph's Providence Porch have Category 2 listings with Heritage New Zealand (formerly New Zealand Historic Places Trust).
As most other New Zealand Schools do, students in years 11âÂÂ13 sit NCEA (National Certificate of Educational Achievement) examinations.