The Estrela Mountain Dog's origin is obscure, but it may be considered one of the oldest breeds of the Iberian Peninsula. These dogs protect the flocks against the wolves and other wild animals in the mountains of Portugal. They can be used as an escort of people because of their remarkable aggression towards strangers, yet obedience to their master. This breed is also an excellent guardian of dwellings and farms.

Also called Cao da Serra da Estrela.