In mathematics, a Sastry automorphism, is an automorphism of a field of characteristic 2 satisfying some rather complicated conditions related to the problem of embedding Ree groups of type ²F₄ into Chevalley groups of type F₄. They were introduced by , and named and classified by who showed that there are 22 families of Sastry automorphisms, together with 22 exceptional ones over some finite fields of orders up to 210.