The Girls' Day School Trust (GDST) is a group of 25 independent schools, including two academies, in England and Wales, catering for girls aged 3 to 18. It is the largest group of independent schools in the UK, and educates 20,000 girls each year. It was formed in 1872 to provide affordable day-school (non-boarding) education for girls as The Girls' Public Day School Company (1872–1905), then The Girls' Public Day School Trust (1906–1998). The GDST is a registered charity. In 2016–17 it had a gross income of £261 million, making it one of the 20 largest charities in the UK.