If you want a comfortable summer shirt then this one is for you! It has great coverage (not too thin, not too thick) and it is incredibly soft against the skin. I consistently fit into size large shirts pretty much across all brands (for women not teenagers). I purchased the XL because I wanted something to lounge in and to fit a bit bigger than I usually wear. This shirt fits like a large would normally fit on me (seems to fit smaller).  If you want something that looks more "tailored"  I'd say stick with the size you normally wear. Otherwise consider ordering a size up for even more flexibility. Don't get me wrong, it's a comfortable shirt... I plan on purchasing lots more... I'll order the size based on what I intend on wearing it with (walking shorts vs. athletics) ..