I normally wear a S in US womens and a M in the Juniors dept, depending on brand. I ordered a M and it fits fine. It’s fairly loose through the body, but I don’t think I could have sized down due to the fit in the shoulder. For reference, I’m 5’6, 140. 36C. 35-30-37. I would recommend ordering 2 sizes up from your US womens size, or the larger of your go to size in the Junior dept.Held up fine in the wash. No defective seems. Overall a good shirt. Pleased with purchase.