St Albans School is a public school in the city of St Albans in Hertfordshire. Entry before Sixth Form is for boys only, but the Sixth Form has been co-educational since 1991. Founded in 948 by Wulsin, St Albans School is not only the oldest school in Hertfordshire but also one of the oldest in the world. The school has been called "Britain's oldest public school" by the Daily Mail. Nicholas Carlisle, in 1818, described the school as "of very ancient origin, and of great celebrity" and the Good Schools Guide describes St Albans as a "traditional public school, with a rich history".

In England and Wales, a public school is a type of fee-charging private school originally for older boys. They are "public" in the sense of being open to pupils irrespective of locality, denomination or paternal trade or profession; nor are they run for the profit of a private owner.