I am 5'11, 165 lbs, athletic build, and an 8/10 in most pants/bottoms. I ordered the Large. When I first took them out, I thought they sent me a small or medium and was worried they wouldn't fit. Lo and Behold!- these tights are amazingly stretchy and hug all my curves. My boyfriend really likes them and complimented them immediately. I love the way they feel, so comfy and stretchy. The pattern is beautiful. My new fav leggings hands down!