Ungnadia is a genus of flowering plants in the family Sapindaceae containing one species, Ungnadia speciosa, the Mexican buckeye. It is native to northern Mexico, as well as Texas and southern New Mexico in the United States. The name honours Austrian ambassador Baron David von Ungnad, who brought the horse chestnut to Vienna in 1576, introducing the plant into western Europe.

The Sapindaceae are a family of flowering plants in the order Sapindales known as the soapberry family. It contains 138 genera and 1,858 accepted species. Examples include horse chestnut, maples, ackee and lychee.