Last name Seyi (Seyi 
, セイ 
) , throughout the world, is a common cognomen. The family name Seyi is habitual in Nigeria, where it is quite a common surname, Japan, where it is quite a rare surname, and Iceland. In absolute terms, this name is the most popular in Nigeria, Japan, and Cameroon. Likewise, Seyi is the forename as well as the last name.