Do you mean off Walt Disney World property? Other than the Magical Express busses that take you to and from the airport, no. There are no Disney buses that can take you to say Universal Studios or Sea World. You'd need to take a taxi or other private service for that, or rent a car.
Disney does have car rental locations on property, so it is possible to rent a car for just a couple of days on your trip and not have to go back to the airport to return it.