A new species of mysidacean crustacean, Orientomysis calida, is described from the Gulf of Thailand. Orientomysis calida resembles O. leptura (Liu and Wang, 1980) but differs in that the second endopodal segment of the maxilla lacks tiny spines on the lateral margin, the exopod of the fourth male pleopod has two subequal terminal setae, and the uropodal endopod has a single spine on the ventral statocyst region. This is the first record of a species of Orientomysis outside East Asian waters.
