Purdiaea is a genus of flowering plants in the family Clethraceae described as a genus in 1846. It is one of two genera in this family, and was formerly classified in the related family Cyrillaceae. Purdiaea is native to tropical regions of the Caribbean (with the highest species diversity on Cuba), Central America and northern South America, further south than the related genus Clethra, the only other genus of this family. The genus is composed of shrubs and small trees with alternating leaves.