I ordered a large which is my typical size - they fit pretty good, but they are a bit high waisted which gets annoying when moving around a lot.  They are a little short - they are called ankle length, but I'm short (5'3") and they just barely reach my ankles.  It works for me, but taller girls beware!  The fabric is very comfortable and very thin.  I gave them a test wear and they really helped keep me much warmer under workout pants when I shoveled in the cold.  I plan to use these for hiking - the material will help wick away sweat and keep me warm without being too much and making me overheat.  Overall, I'm quite satisfied.