The National Association of Supplementary Schools (NASS) was formally set up in October 1987 to unite and guide the work of Black Supplementary Schools nationally. NASS grew out of the Black Education Movement and the Black Parents Movement, active since the late 1960s to secure improvements in the education of black children.

NASS officers elected at the Inaugural Meeting on 18 October 1987 were: Chairman: John La Rose; Vice Chair: Valentino Jones; Secretary: Mavis Milner-Brown; Assistant Secretary: Anthea Thorpe; Treasurer: Andrew Johnson; Assistant Treasurer: Sam Robin-Koker; Public Relations Officer: Gordon de la Mothe.

Based on the principle of self-reliance and self-help, NASS had a membership fee of £20 and its motto was 'We are our own educators'. Its key aims were: (a) Provide guidance and support to community groups wishing to establish new supplementary schools. (b) Influence governmental and Local Educational Authorities' policies to introduce change in mainstream school curriculum and practices. (c) Promote partnerships between parents, mainstream schools and supplementary schools. (d) Build a resource unit to assist in the dissemination of relevant information to parents, teachers and young people.

Funding contributed by the Inner London Education Authority (ILEA) enabled affiliated NASS members to develop courses on black history, culture and identity alongside national curriculum subjects. This extended provision enabled the development of black community and youth services, which were instrumental in helping young black people build skills and self-confidence.

The abolition of the Inner London Education Authority (ILEA) in 1989 by Prime Minister Margaret Thatcher impacted the work of NASS and its members in an important way, as its projects were funded by the ILEA. By the 1990s, the formal role of NASS had weakened, even though correspondence and documents relating to various black educational issues continued to be received and collected beyond the year 2000.