In my opinion, the seat holds even better on the back seat, because it is best to have two seat belt fasteners. One is to put the seat belt around the seat and then fasten it as usual, and the other is to pull a dog seat belt, which is fastened to the dog's harness, through a slot in the seat and put it into the seat belt buckle. So you need a separate dog seat belt so that the dog can also be properly secured :)