I love this dog bed.  The dog I bought this for weighs around 60 lbs and seems to be too big to fit inside the large.  Our 40 lb dog loves it though.  I love the dog bed.  Our 40 lb dog sleeps so soundly inside his bed.  It is hilarious.  If you have a bigger dog, you may want to consider the XL size.  Our 60 lb dog is short and very stocky.