I am 5'4",150lb, 36B and purchased a medium. This is a very comfortable shirt and fairly soft. Like others mentioned, it is see-through enough that I would wear a cami underneath. I wore a beige one and you can see it in the armpit area, but with a strap adjustment, it can be hidden. I like the way it fits, although, I will mention that it accentuates the hips and doesn't fall flat on the front (which is typical of this style shirt, but I would have preferred it be less so), so it adds what coulSee full review