I wear a mens S/XS and I actually bought a medium bc all the men that reviewed this complained that it was too small. It is exactly the size of a medium mens shirt that youd find at Hottopic or JCPenny. In fact, this is a brand that is sold at Hottopic. Its actually too big for me because I listened to these reviews. Its a great shirt and now I look like a walking tent in it. Go with the sizing chart. Follow your heart.