三棱齿兽科（学名：Tritheledontidae）也被称为鼬龙类（Ictidosauria），是群小到中型的犬齿兽类，身长约10到20公分。

在1912年，南非古生物学家罗伯特·布鲁姆（Robert Broom）创建三棱齿兽科。在某些文献中，曾被误拼为「Trithelodontidae」。

三棱齿兽科是极度类似哺乳类且高度特化的犬齿兽类动物，但是牠们的生理结构上仍保留许多爬行动物的特征。三棱齿兽科是从基础真犬齿兽类动物演化而来，像是犬颌兽。三棱齿兽科主要是肉食性或食虫性，虽然有些物种已经发展出杂食性的特征。三棱齿兽科的化石显示出牠们与哺乳类有接近亲缘关系。三棱齿兽类是存活最久的非哺乳类兽孔目之一，从晚三叠纪存活到中侏㑩纪。目前不清楚为何这群动物在侏㑩纪灭绝。一个可能的解释是牠们与其近亲哺乳类的竞争失败。大多数侏㑩纪的哺乳类是肉食性动物，而且可能会捕食三棱齿兽类。一群称为三尖齿兽目（Triconodonta）的肉食性哺乳类，首次出现在晚侏㑩纪，牠们可能猎食任何小型动物，包括深处危险的三棱齿兽类。三棱齿兽科的化石发现于南美与南非，显示出牠们存活在盘古大陆南部。

The Tritheledontidae or tritheledontids, also known as ictidosaurs, were small to medium-sized (about 10 or 20 cm long) cynodonts. They were extremely mammal-like, highly specialized cynodonts, although they still retained a very few reptilian anatomical traits. Tritheledontids were mainly carnivorous or insectivorous, though some species may have developed omnivorous traits. Their skeletons show that they had a close relationship to mammals. Tritheledontids or their closest relatives may have given rise to primitive mammals. The tritheledontids were one of the longest lived non-mammalian therapsid lineages, living from late Triassic to the Jurassic period. Tritheledontids became extinct in the Jurassic period, possibly due to competition with prehistoric mammals such as the triconodonts. They are known from finds in South America and South Africa, indicating that they may have lived only on the supercontinent of Gondwana. The family Tritheledontidae was named by South African paleontologist Robert Broom in 1912. The family is often misspelled "Trithelodontidae".