Tag says small. Could fit a women’s loose small or a slim medium Beautiful butterfly shirt Could be a men’s XS Chest 18 inches across Shoulders 16 inches across Length 26 inches The arm opening is kinda small 6 inches diameter so 12 inches around. I’m usually a men’s small medium and my arm bicep area couldn’t fit so I’m guessing it’s a woman’s size. How ere a very slim man or XS could fit it also.