This is the second time I have bought these shirts for my construction/building maintenance job. I am 5'4, 140 lbs, athletic build. I have a short torso, so the shirt fits a bit long, but I like that for the work that I do. I purchased a medium, and the fit is perfect for what I wanted - not too loose, but with room for movement. If I were purchasing this for casual wear and not for work, I would order a small. The colors are great, and the fabric is super soft.