The Girls' school and its brother school, Watford Grammar School for Boys, descend from a Free School founded as a charity school for boys and girls by Elizabeth Fuller in 1704 and refounded as a secondary school in 1884. The school has occupied its present site in central Watford since 1907. The name Watford Grammar School for Girls dates from 1903. Although the school ceased to be a tripartite systemgrammar school in 1975, it retains some features of the grammar school tradition. The school site is divided in two by a public footpath, with a footbridge spanning the path to connect the two parts. The northern part includes a former private house, Lady's Close now used as the English block. Also in the northern part is the PE block and Fuller Life Gym, open to members of the public in non-school hours. A new building, Hyde House, is also situated in the northern part. Except during the First World War, when it was taken over by the Red Cross as an auxiliary hospital, the building served as the school's preparatory department until that department was closed in 1944. Since then it has served as the home of the entry form to the school.
The school today
Watford Girls has been partially selective since 1995, though the proportion of selection has been reduced over this period. The school also gives priority to sisters of current pupils at the school. Prior to 2008 it also gave extra consideration during the selection process to sisters of pupils of Watford Grammar School for Boys. Its admission area reaches out about, including some northern parts of the London boroughs of Harrow and Hillingdon. In comparison with the national average, its intake has significantly higher academic attainment, greater ethnic diversity and fewer children receiving free school meals. An inspection in 2007 by the Office for Standards in Education rated the school as outstanding in all categories. It has long been near the top of performance tables for comprehensive schools, but when the key measure at GCSE was changed in 2007 to include English and mathematics the school moved to the top position. The then-headmistress, Dame Helen Hyde, attributed part of their success to De Bono Thinking Tools, for which the school was one of the first in the United Kingdom to receive accreditation as a national training school.