These board shorts are sized for someone with absolutely zero behind. I wear a 36 in absolutely everything I wear, and that is actually half a size too big. And these shorts fit absolutely perfectly - for my legs. I am an Adonis by no means, but I do not have a huge butt either.I literally could not even get these board shorts on. I think technically, they do have a 36" waist or just shy of it, but I think it actually gets slimmer between the waist line and the leg holes. I do not know if there is something going on with the measurements on my pair or if O'Neill just designed them this way, but I would probably have to get a size 40 to make these ratios work.