The Thai horseshoe bat (Rhinolophus siamensis), sometimes called the Thai leaf-nosed bat, is a species of bat from the family Rhinolophidae. It is frequently listed as a subspecies of the Big-eared horseshoe bat, but this may be a result of the two species being taken in sympathy in Laos. It is native to China, Laos, Thailand, and Vietnam. The species is listed as Least Concern on the IUCN Red List, as its extent of occurrence is much larger than 20,000 km², and there is little likeliness that its population is declining quickly enough to qualify for listing in a more threatened category.