The sublingua ("under-tongue") is a muscular secondary tongue found below the primary tongue in tarsiers and living strepsirrhine primates, which includes lemurs and lorisoids (collectively called " lemuriforms"). Although it is most fully developed in these primates, similar structures can be found in some other mammals, such as marsupials, treeshrews, and colugos. This "second tongue" lacks taste buds, and in lemuriforms, it is thought to be used to remove hair and other debris from the toothcomb, a specialized dental structure used to comb the fur during oral grooming. Tarsiers have a large but highly generalized sublingua, but their closest living relatives, monkeys and apes, lack one.

The sublingua is thought to have evolved from specialized folds of tissue below the tongue, which can be seen in some marsupials and other primitive mammals. Simians do not have a sublingua, but the fimbria linguae found on the underside of ape tongues may be a vestigial version of the sublingua.