胡麻科属于唇形目，又名苣蕂。全世界有14属70种。中国二属二种，胡麻属的芝麻与茶菱属的茶菱。

胡麻科在1981年的克朗奎斯特分类法中被分到玄参目中，并将角胡麻科（Martyniaceae）也分入本科，两科的植物都具有毛，所以叶子和茎都有一种喇手的感觉，果实都类似角状，但最新的依据基因亲缘关系分类的APG 分类法认为两类植物的关系并不近，因此将角胡麻类植物单独分为一个科，将这两个科分入唇形目。

Pedaliaceae (pedalium family or sesame family) is a flowering plant family classified in the order Scrophulariales in the Cronquist system and Lamiales in the Angiosperm Phylogeny Group system. Cronquist included the family Martyniaceae in Pedaliaceae, but phylogenetic studies have shown that the two families are not closely related and they are maintained as separate by the APG. Both families are characterized by having mucilaginous hairs, which often give the stems and leaves a slimy or clammy feel, and often have fruits with hooks or horns.