Ok, first, I, think these should be called "capri pantyhose" because you can see right through them!!! So I thought that maybe a medium was too small but I'm 5'6" and 138 lbs, so I fall right where I should, going by the chart on the back of the package. Second, they have a cotton crotch that is visible from the outside. I HATE THAT! My advice is if you weigh more than 135 lbs. go ahead and order a large, they will not be too big and don't plan on wearing these unless your backside is thoroughly covered. Oh yeah, they don't fall on your leg like the picture shows, they stop right below your knees.