The main difference between a support dog and a service dog lies in their specific tasks and legal protections. A service dog is trained to perform specific tasks to assist an individual with a disability, such as guiding the blind or alerting someone with diabetes of low blood sugar. Service dogs have legal access rights to accompany their handlers in public places. In contrast, a support dog provides emotional support for its owner but does not undergo the same rigorous training as a service dog and does not have the same public access rights.