St Margaret's School was founded by Mrs Maria Dyer in 1842, making it the oldest girls' school in Singapore and the Far East. Maria Dyer was a young missionary of the London Missionary Society. She was inducted to the Singapore Women's Hall of fame in 2014 under the category of Education. The school was then known as Chinese Girls' School and it was located in a shophouse at North Bridge Road.
The first Principal was Miss Grant. The girls were taught the Christian faith, given an elementary education and above all, equipped to be good homemakers. They were trained to be independent, with special emphasis on character building and leadership. This has been a tradition for more than 165 years.
In 1861, the school was relocated from North Bridge Road to 134 Sophia Road. In 1900, the name of the school was changed to CEZMS (Church of England Zenana Missionary) School. In 1939, the school became a Grant-in-Aid school and a day school for girls of all races. In 1949, the late Bishop Wilson renamed the school St Margaret's School, in honour of Queen Margaret of Scotland.
Miss Norah Inge became the Principal in 1948. Domestic Science became part of the school curriculum, a netball team was formed and a Girl Guide Company was incorporated.
1960 saw the separation of the Primary and Secondary sections. The Secondary school moved to Farrer Road. The familiar old building at 134 Sophia Road which continued to house the Primary School was finally demolished in August 1984. While awaiting the completion of the new building, the school occupied a holding school in Anthony Road. The shift back to the old site came in June 1986, with a new address - 99 Wilkie Road. The new building was officially opened by the Member of Parliament for Ulu Pandan, Dr Dixie Tan on St Margaret's Day, 16 November 1987.
In 1999, the school underwent PRIME (Programme for Improving Existing Schools) on-site. On 16 November, the National Heritage Board recognised the school's long-standing history in Singapore by marking the school's site at Wilkie Road a national historic site. In 2001, the upgrading of the Primary School was completed.
Founded in the spirit of charity, patience and devotion - the school motto, the school, with a record of helpfulness, good works and dedicated service, is well loved by all who have passed out of her gates and will be loved and honoured by those yet to come. This is our heritage - a girls' school with a tradition of service to our neighbours, our community and our nation.