NIOS is "Open School" to cater to the needs of a heterogeneous group of learners up to pre-degree level. It was started as a project with in-built flexibilities by the Central Board of Secondary Education (CBSE) in 1979. In 1986, the National Policy on Education suggested strengthening of Open School System for extending open learning facilities in a phased manner at secondary level all over the country as an independent system with its own curriculum and examination leading to certification.
The National Institute of Open Schooling (NIOS) formerly known as National Open School (NOS) was established in November,1989 as an autonomous organisation in pursuance of National Policy on Education 1986 by the Ministry of Human Resource Development (MHRD), Government of India. NIOS is providing a number of Vocational, Life Enrichment and community oriented courses besides General and Academic Courses at Secondary and Senior Secondary level. It also offers Elementary level Courses through its Open Basic Education Programmes (OBE).Government of India through a gazette notification vested NIOS with the authority to examine and certify learners registered with it upto pre degree level courses whether Academic, Technical or Vocational. Association of Indian Universities, vide letter No . EV/11(354)/91/ 25 July, 1991 issued Equivalence of Senior Secondary Certificate Examination of NIOS.