Harrow County School for Girls, sometimes called Harrow County Grammar School for Girls, was a grammar school located in Lowlands Road in Harrow, now part of Greater London but in Middlesex at the time of construction. It was established in 1914. It closed in 1975 when the London Borough of Harrow adopted a comprehensive system of education. The site was then used by Lowlands Sixth Form College, later becoming Greenhill College and since 1999 Harrow College.