I'm about 5'4"-5'5" and 115 lbs and I bought the OAK in S. Very cool jacket. Easily recognisable. I have slightly wider shoulders for my height and this fits pretty well, a little baggy looking but it feels great. Length-wise it's just right. I wore it with a tank top inside and a DAKINE Heavy-Weight Realm 1/4-Zip and I'm pretty much good to go. I highly recommend you to get this! It's so pretty!