The Postgraduate Institute of Science (PGIS) is a National Institute established by the Ministry of Education and Higher Education in 1996, by an ordinance made by the University Grants Commission under section 18 with section 24A of the Universities Act No. 16 of 1978, for the purpose of providing, promoting and developing higher education in science.

The PGIS is attached to the University of Peradeniya and depends on the university for formulation and implementation of its academic programmes and the award of postgraduate degrees.