I ordered a M, but am also going to try a L just to be safe. Either way, it seems to run a bit small. I'm 5'5 and 125lbs, but my upper body is a little more muscular because I'm an aerialist, so maybe that's why. I love the thumb holes and it feels well made. Definitely a piece that can be mixed and matched in the future.
I obviously did not read the description closely enough, as the picture shows this top WITH another top under it. As it is, it is just a completely mesh shirt. My bad for not reading better I guess. I have not decided if we are keeping it or not, as it will require an additional purchase of another top. If you are looking for a completely mesh shirt though, this one looks pretty nice. We ordered it in the nude color and the material is nice and it looks well-made.