Sanjiwani Secondary School was established as Sanjiwani Middle English School in 1949 as a sanctuary for education to enlighten the local people as to freeing them from the confinement of ignorance. The school was upgraded to High School in 1957 on the basis of the standard of education, physical facilities and setting and sound educational environment as well as the extension of its catchment area.
The school was modified as Multi- purpose School in 1976, as Vocational Secondary School in 1971, as Model School in 1977 and finally as General School in 1981 after the amendment of National Education System Plan which abolished the categorization of secondary schools. In 1991, the school was upgraded to Secondary School affiliated to Higher Education Board with 10+2 Management Stream.
In 1999, 10+2 Education Stream was added and in 2003, 10+2 Science Stream was launched with the academic support of Kathmandu University. Besides these wings, the school has been running separate English Medium School from Grade nursery to Ten since 1982 and Integrated Education Program for the Blind since 1986.
In 2006 Higher Secondary Education Board selected the Higher Secondary (10+2) section of the school as a Model Higher Secondary School for quality education and easy access to higher education as well as developing it as a leading school in the district.