Assistance dogs can provide a multitude of tasks, depending on the disability of the handler. They can retrieve items, open and close doors, turn the lights on and off, assist in balance, carry items etc. An assistance dog commonly helps with handler mobility issues.

All service dogs must be public access certified. This requires considerable training and temperament stability so that the public is safe and the team is controlled. Most dogs that fail to become certified service dogs do so because they fail the public access criteria.