The Sri Lanka bay owl (Phodilus assimilis) is a species of bay owl in the family Tytonidae. It is endemic to the island of Sri Lanka and the Western Ghats in Kerala, South Western India. It was considered a subspecies of the Oriental bay owl (Phodilus badius) but is now treated as a full species due to its distinctive call, plumage and disjunct distribution.
Its natural habitats are subtropical or tropical moist montane forests and subtropical or tropical high-altitude grassland. It is threatened by habitat loss.