The school was founded in 1865 as the Royal School for Daughters of Officers of the Army. Royal status came from Queen Victoria who, along with Florence Nightingale, wanted to provide education for daughters of officers lost in the Crimean War. Initially established as a boarding school, the boarding facilities remain to this day, but from the early years the school gradually opened its doors to day girls too.The Royal School has had an outstanding history lasting more than 130 years. Improvements and extensions to the original buildings on the Lansdown site were made as required, along with the purchase of additional buildings for boarding facilities.

When the school buildings in Bath were commandeered by the Royal Navy in 1939 for use during the Second World War, the school moved for eight years to the Longleat Estate, at the invitation of Lord Bath. The evacuated girls lived in the main building, alongside his Lordship, and remained there until returning to Bath in October 1947.

In 1998 the Royal School merged with another local school, Bath High, and has since operated as the Royal High School.