Four mosquito species that occur in the Oriental and Southeast Asian regions are reported for the first time from Sri Lanka. They are Aedes (Diceromyia) periskelatus (Giles), Aedes (Verrallina) yusafi Barraud, Culex (Culiciomyia) scanloni Bram and Uranotaenia (Pseudoficalbia) gouldi Peyton & Klein. Brief notes on the biology of these species are provided. Another species, Culex (Culex) hutchinsoni Barraud, is provisionally identified as occurring on this island.