Premasiri is both a given name and a surname. Notable people with the name include:
Premasiri Khemadasa (1937–2008), Sri Lankan music composer Halambage Premasiri (1962–2016), Sri Lankan cricketer Lionel Premasiri, Sri Lankan politician P. D. Premasiri (born 1941), Sri Lankan Buddhist scholar Ranjith Premasiri Madalana, Sri Lanka Army sniper