Queen Elizabeth's Grammar School, Horncastle is a co-educational grammar school with academy status in Horncastle, Lincolnshire, England. In 2009, there were 877 pupils, of whom 271 were in the sixth form. Although royally chartered by Queen Elizabeth I in 1571, there had already been a school in Horncastle for two hundred and fifty years. The original charter document, with its royal seal, remains in the custody of the school's governors.