Saint Felix School is a 2–18 mixed, private, day and boarding school in Reydon, Southwold, Suffolk, England. The school was founded in 1897 as a school for girls but is now co-educational.

The school was founded in 1897 as a girls' school by Margaret Isabella Gardiner.^{[citation needed]}

By September 1902, the present site of the school had been purchased and the first four boarding houses and teaching block completed. In 1909 Lucy Mary Silcox took over as headmistress from the founding head. The student roll grew and in 1910, the Gardiner Assembly Hall and a Library were built and Clough House followed in 1914.

Silcox was able to bring leading thinkers and artists to the school and money was found to buy sculpture and paintings. The modernist paintings inspired pupils like the artist Gwyneth Johnstone who remembered seeing work by Christopher Wood at the school. Silcox directed the girls in ancient Greek plays. The students knew she was President of the local National Union of Women's Suffrage Societies as she gave talks in surrounding villages in support of women gaining the vote. The school continued during the 1914-18 war and during the 1916-1917 school year there was an outpost of the school at Penmaenmawr as some parents were worried about their students' safety. The whole school was evacuated three times and the school took in some Serbian refugees.

The school accommodates toddlers from 2 years of age in the Little Saint Felix Nursery, and children up to the age of 18 in the Sixth Form. The school offers boarding throughout the term, weekly, or 'flexi' boarding. Having joined the School in September 2023, Mr Matthew Oakman is the current Head.