畸齿龙科（Heterodontosauridae），又名异齿龙科，意为「有不同牙齿的蜥蜴」，是鸟臀目恐龙的一科，经常被认为是群基础鸟脚类恐龙，但最近的研究显示畸齿龙科与头饰龙类关系密切。虽然畸齿龙科的化石很罕见，牠们从侏罗纪早期存活在全球各地，少数物种存活到白垩纪早期。

畸齿龙科的体型如狐狸般大小，身长少于2公尺。畸齿龙科因牠们的独特牙齿而著名，包括类似犬齿的长牙、以及适合咀嚼的颊齿，颊齿与白垩纪鸭嘴龙科的牙齿类似。畸齿龙科是草食性恐龙，或可能是杂食性。

Heterodontosauridae is a family of early ornithischian dinosaurs that were likely among the most basal (primitive) members of the group. Although their fossils are relatively rare and their group small in numbers, they lived across all continents except Australia and Antarctica for approximately 100 million years, from the Late Triassic to the Early Cretaceous.