牻牛儿苗科（学名：Geraniaceae）共有7-11属约800余种，分布在世界各地的温带和亚热带地区，也有少数种生长在热带，中国有4属70余种。比较重要的属是老鹳草属（430余种）、天竺葵属（280余种）和牻牛儿苗属（80余种）。基本为草本或亚灌木。单叶，互生或对生；花两性，基本为5基数，雄蕊或5的倍数；蒴果通常有长喙，室间开裂。多种可供药用，天竺葵原生于南非，先被世界各地广泛引种并培养出多种变种，作为观赏花卉。

Geraniaceae is a family of flowering plants placed in the order Geraniales. The family name is derived from the genus Geranium. The family includes both the genus Geranium (the cranesbills) and the garden plants called geraniums, which modern botany classifies as genus Pelargonium, along with other related genera.