Nirmal Ranjith Dewasiri (also spelled Devasiri)(Sinhala: ආචාර්ය නිර්මාල් රංජිත් දේවසිරි ) born on 18 October 1965 is Senior Lecturer of the department of history at the University of Colombo, Sri Lanka.

[2] He specialises in social transformation in agrarian societies, history and ideology, European colonialism in Asia, post-colonial state-building, and ethno-nationalism.

His BA thesis explored the political impact of Rohana Wijeweera, the charismatic leader of two armed insurrections of Southern Province, Sri Lanka.

[3] In pursuing his master's degree, he analyzed the formation of Sinhala nationalist ideology in the nineteenth and early twentieth centuries.

[6] His doctoral thesis, The Adaptable Peasant: Agrarian Society in Western Sri Lanka under Dutch Rule, 1740 1800 studied the impact of the Dutch East India Company(VOC) on western Sri Lanka's agrarian society.