Tenuis, weak or slender in Latin, and a species in zoology, may refer to:
Language Tenuis consonant, an obstruent (stop, affricate or rarely fricative) that is voiceless, unaspirated and unglottalized.
Zoology Acropora tenuis is a species of acroporid coral found in the Red Sea, the Gulf of Aden. Anatoma tenuis, a species of minute sea snail. Copulabyssia tenuis, a species of sea snail. Chromodoris tenuis, a species of colourful sea slug. Dirofilaria tenuis, a species of nematode parasitic roundworm. Hierodula tenuis, a species of praying mantis in the family Mantidae. Maoricicada tenuis, a species of insect that is endemic to New Zealand. Montebello tenuis, a monotypic genus of Australian ground spiders. Odostomia tenuis, a species of sea snail. Tenuiphantes tenuis, a species of spider. Tenuis tetra, a fish species. Triplophysa tenuis, a species of ray-finned fish.