The NAHT, formerly and still officially known as the National Association of Head Teachers, is a trade union and professional association representing more than 28,500 members in England, Wales and Northern Ireland. Members hold leadership positions in early years; primary; special and secondary schools; independent schools; sixth form and FE colleges; outdoor education centres; pupil referral units, social services establishments and other educational settings.
The union was founded in 1897 as the National Federation of Head Teachers' Associations. Membership grew from just over 1,000 in 1898 to 10,000 in 1947, and 20,000 by the 1980s. For many years, membership was restricted to headteachers, but deputy headteachers were admitted from 1985, and assistant headteachers from 2000.