World’s smallest dog..... The smallest dog in history was a tiny Yorkshire Terrier from Blackburn, England. At two years of age and fully grown this little dude was an incredible 2.5 inches (6.35 cm) tall by 3.75 inches (9.5cm) long! He weighed only 4 ounces (113grams)! He was approximately the size of a matchbox. Gotta love that face.... Yorkie