Simethis is a genus of plants in the family Asphodelaceae, subfamily Hemerocallidoideae. It contains only one known species, Simethis mattiazzii, commonly called the Kerry lily. It grows in dry places especially near the coast in western Europe (Ireland, France, Spain, Portugal, Italy) and northern Africa (Algeria, Morocco, Tunisia). Its common name is based on its occurrence at a few sites in County Kerry, Ireland.