I’m wearing a small in both pieces... The top I’m wearing is from my lingerie collection the name of the lingerie is “Ms Spicy” it is stretchy and fitted. The bottoms I normally wear a small in but In this material had to do a medium so my suggestion to you is what ever size you normally wear go up a size in these they are stretchy but extra fitted .. It has belt buckles going down the sides of both legs that can be readjusted to fit you as loose or as tight... This is a high quality item. The pants zip in the back and are high waisted to help give a more hour glass shape and extra support.