I am 5'1, 135 lbs. I usually wear a size 8 or 10. The first time I bought a pair of these shorts, I bought a large. I had to return it. It was WAY too small. I liked the material and I still needed something to wear under my summer dresses when I'm teaching preschoolers and elementary grade kids. (I like to go down the slides with the kids, etc.) So the second time, I bought a 2X-large. It fit okay. I'm thinking about buying another pair of 3X-large. They are VERY tight. Maybe it's just my build. In dresses and jeans, I am a size 8 or 10. In shorts I am a size 12. In leggings, I usually buy xlarge. I gave it 4 stars because the material is great and it is exactly what I was looking for. Just be ware that if you are a "pear" or steep hourglass, you have to buy it a size, two, or three larger than your jean size.