The Postgraduate Institute of Humanities and Social Sciences (PGIHS) is a National Institute established by the Ministry of Higher Education in 2014, by an Ordinance made by the University Grants Commission under Section 24A of the Universities Act No. 16 of 1978 and published in Gazette Extraordinary No. 1843/45 of 3rd January 2014 for the purpose of providing, promoting and developing higher education in the Humanities and the Social Sciences. The PGIHS is the heir to the postgraduate programmes offered by the Faculty of Arts of the University of Peradeniya.

The PGIHS offers postgraduate degree and diploma programmes and other short-term training programmes with an interdisciplinary and a multidisciplinary orientation. At present, the PGIHS caters to approximately 2000-2500 students annually following courses leading to postgraduate diplomas, masters and doctoral degrees in 26 different disciplines under five Boards of Study. About 700 students complete postgraduate diploma, masters and doctoral degrees annually at the PGIHS.

The disciplines that the PGIHS provided training include: Arabic, Accounting, Archaeology, Buddhist Studies, Comparative Religion, Economics, Education, English, Fine Arts, Geography, Greek and Roman Studies (formerly known as Western Classical Culture), Hindu Civilization, History, International Relations, Islamic Civilization, Law, Management, Pali, Philosophy, Political Science, Psychology, Sanskrit, Sinhala, Sociology, Statistics and Tamil.

The PGIHS aims at becoming a centre of excellence in education, research, and creative thinking in the Humanities and the Social Sciences and to produce scholars committed to the advancement of knowledge through critical and independent thinking with a sense of duty toward society.