After my son's birth I upped my bustline to a 32H.  So I'm busty with a smaller waist.  I got the Medium.  This shirt fits amazing.  It's my #1 weekend cruising shirt with my little man.  It's cute and stylish with good coverage.  The only issue I find is it's hard to access the openings under the top portion with only one hand.  Since I don't use it a lot for public feeding, this isn't really a big issue for me.