I’m 5’3” and 121 lbs, and a size S fits me perfectly. I absolutely adore this set. The fabric is soft, cozy, and wonderfully lightweight, with nicely roomy cuffs that make everyday movement so easy. What I love most is the stretch elastic waistband on the pants — it’s effortless to slip on and off, never tight or restrictive at all. I feel completely free and comfortable all day long, no matter what I’m doing.