The Postgraduate Institute of Humanities and Social Sciences (PGIHS) is a national Postgraduate Institute affiliated to the University of Peradeniya and functions under the University Grants Commission. Though the Ordinance establishing the PGIHS was issued in December 2013, the formal operations of the new Institute commenced only in 2015 when the new Director and the Board of Management was appointed by the UGC and took over the postgraduate programmes that were, until then, managed by the Postgraduate Unit of the Faculty of Arts. The Institute is housed in a building on Galaha Road adjoining the main Arts Faculty complex of the University across from the University grounds.
The PGIHS presently conducts postgraduate degree and diploma programmes and short-term training programmes in 20 different disciplines under five Boards of Study. Students have the option of choosing either a programme in their preferred discipline or one that is interdisciplinary in content. The disciplines that the PGIHS provide academic training include Arabic, Accounting, Archaeology, Buddhist Studies, Economics, Education, English, Fine Arts, Geography, Greek and Roman Studies (formerly known as Western Classical Culture), Hindu Civilization, History, Islamic Studies, Management, Pali, Philosophy, Political Science, Psychology, Sanskrit, Sinhala, Sociology and Tamil. The Institute caters to around 2500 students at any given time. About 800 students complete postgraduate diploma, masters and doctoral degrees annually at the PGIHS.