I am usually a size S with waist 26/27. The skirt and top fit great but there's slight room especially in the top, so I would recommend this for a true size M, or if you want a more babydoll, loose look, a size S can definitely wear this (: perfect for festivals, beachside vacations, casual dinner with some kitten heels. Such a cute set, I wore it in nyc and the compliments were neverending!