The original foundation deed of the school reads: "We the said Kitherina (Katherine), attentively considering that the purposes of man desiring to be informed in grammar which is the foundation of all liberal arts, is daily defeated and frustrated by poverty and want of means; therefore for the maintenance and exaltation of Holy Mother Church, and the increase of divine worship, and other liberal arts and sciences, out of the goods bestowed on us by God have procured the said Walter and Williams to acquire certain lands and tenements in fee, that they may build a school-house in Wotton for the habitation and likewise dispose of them for the maintenance of a master and 2 poor scholars of the art of grammar; which master and his successors shall govern and inform all scholars coming to the same house or school coming for instruction in this art without taking anything for his trouble from them or any of them."

In January 1963, the school vacated the premises in Wotton and moved into a new building for 350 pupils in the Kingswood Road.

The extensions were completed for the start of the Autumn Term 1973, when Katharine Lady Berkeley's re-opened as a comprehensive school for 830 pupils.

[5] In 1984 the six hundredth anniversary of the foundation of the school was celebrated with a visit from Princess Anne.

In 1992, grant-maintained (GM) status was attained,[7] with the object of providing for the structural improvement of the buildings and a wish to be able to make independent decisions to suit the school's future.

In autumn 1999, work began on further new buildings to provide a new two storey teaching block that includes 11 classrooms, three ICT suites and a new library.