水甘草属（学名：Amsonia）是夹竹桃科下的一个属，为草本植物。该属共有30种以上，分布于北美及东亚。

Amsonia is a genus of flowering plants in the dogbane family, Apocynaceae, first described as a genus in 1788. It is native primarily to North America with one species in East Asia and another in the eastern Mediterranean.

Amsonia is named in honor of the American physician John Amson. Members of the genus are commonly known as bluestars.