Family name Piyadej (Piyadej 
) , across the world, is an extremely rare cognomen. Much more frequently, Piyadej is the forename as well as the last name.
Gridtham, Chaikiturajai, Pongtankul, Ekawaravong, Kalyanamit, Vongchansilp, Pornpithaksuk, Wongsirikul, and Vijaranakorn