Absolutely! Small dogs can be trained to use a litter box. My personal experience shows that small dogs, once trained, actually benefit from using a litter box. Little dogs have small bladders, and the opportunity to "go whenever" is a big plus! It's also possible to train a dog to use a litter box that formerly used papers or went outside. Dogs can also travel using the litterbox in other places, and are able to use the litterbox during the day, as well as "go outside" at other instances.