I wear size 10-1/2 full leather hiking boots and bought the medium size in these gators. I intend to wear them mostly during the summer while wearing jeans or lighter weight pants. They fit fine without any bagginess. They're fairly close fitting but not tight. I think size medium or large would be fine for me. According to RAB, however, the medium is supposed to fit a boot size 8-10 and large 10-13+.