紫草科（学名：Boraginaceae），包括大约100余属共2000多种分布在全世界的植物，有木本植物也有草本植物，有乔木也有灌木。以叶有茸毛为特征。分布于热带及温带，主要集中于地中海地区。叶常互生，为单叶，花鲜蓝色，有时带红色，漏斗状或筒状并向外张开，花冠裂片5，花常俯垂或排成蝎尾状聚伞共序。该科有一些种类，可以做为小规模观赏类植物。

根据克朗奎斯特分类法，紫草科属于唇形目，但根据APG II 分类法，紫草科属于I类真菊分支，可是不属于任何一目，是一个独立的科。根据其基因判断，紫草科和田基麻科植物基因亲缘较深，但APG II 分类法已经将田基麻科植物划归入紫草科，目前有的分类法将紫草科植物划入几个不同的科。

The Boraginaceae, the borage or forget-me-not family, includes a variety of shrubs, trees, and herbs, totaling about 2,000 species in 146 genera found worldwide.

According to the APG II, the Boraginaceae belongs among the euasterid I group, including the orders Gentianales, Lamiales, and Solanales, but whether it should be assigned to one of these orders or to its own (Boraginales) is still uncertain. Under the older Cronquist system it was included in Lamiales, but it is now clear that it is no more similar to the other families in this order than they are to families in several other asterid orders. The Boraginaceae is paraphyletic with respect to Hydrophyllaceae and the latter is included in the former in the APG II system. In some recent classifications the Boraginaceae is broken up into several families: Boraginaceae sensu stricto, Cordiaceae, Ehretiaceae, Heliotropiaceae, Lennoaceae, and Hydrophyllaceae.