The Old English Sheepdog.
The dog from the movie, The Shaggy Dog, is a Bearded Collie.
The dog in the movie 'the Shaggy Dog' comes from a Tibet monastery so the logical conclusion is that it's a Dokhi Apso, a very old Tibetan breed that is known in the west as Tibetan terrier. Although...
An old english sheep dog
A Bearded Collie.