Pet Dress Stevie is 11lbs and is wearing a size medium. Pet Dress SizingSizeNeckLengthGirthWeightSM9"10"13"3-6 LbsMD10"12"16"6-10 LbsLG12"14"18"10-14 LbsXL13"16"20"14-20 Lbs2XL14"18"22"20-25 Lbs3XL18"20"24"25-35 Lbs