The Bernese Mountain Dog, called in Swiss German the Berner Sennenhund, is a large breed of dog, one of the four breeds of Sennenhund-type dogs from the Swiss Alps. Like the other Sennenhunds, the Bernese Mountain Dog is a large, heavy dog with a distinctive tricolored coat, black with white chest and or rust colored markings above eyes, sides of mouth, front of legs, and a small amount around the white chest. An ideal of a perfectly-marked individual gives the impression of a white horse shoe shape around the nose and a white “Swiss cross” on the chest, when viewed from the front.

The Bernese Mountain Dog, like all dogs, is descended from the wolf. The breed was used as an all purpose farm dog, for guarding property and for driving cattle into the ground. The breed standard for the Bernese Mountain Dog states that dogs should not be "aggressive, anxious or distinctly shy," but rather should be "good natured," "self-assured," "placid towards strangers," and "docile."