Sea hares, also known as sea slugs, belong to family Aplysiidae and are very common in intertidal and subtidal areas of the ocean around the world. Yet, very little research is being conducted on this group in Taiwan. Some individuals of species Stylocheilus striatus (Quoy & Gaimard, 1832) were found in southern Taiwan. In this study, we document the first report of S. striatus from Taiwan and discuss its misclassification as a similar species, S. longicauda (Quoy & Gaimard, 1824).