The name Fox Terrier or Foxy refers primarily to two different breeds of dog, the Smooth Fox Terrier and the Wire Fox Terrier, that were independently bred in England in the mid-19th century. The two terrier breeds are very similar, with the only major difference being the coats. The Smooth Fox Terrier has a smooth, flat, but hard and dense coat, whereas the Wire Fox Terrier coat should appear broken with a dense, wiry texture.

Today, there are many and varied breeds that are descended from or related to earlier fox terrier types. These include the breeds outlined below:

The Brazilian Terrier is one of only two breed of dog developed in Brazil. It is one of several terriers probably descended from the combining of the Fox Terrier with other small breeds. It has been established in Brazil for about 100 years. This hound is a pack hunter which tires its prey by surrounding it and terrorising it into submission. It is also an excellent catcher of vermin.

The Japanese Terrier is a small terrier native to Japan. It is believed to be descended from the progeny of fox terrier types, pointers and indigenous Japanese dogs. This dog is also known as the Nippon Terrier. The breed is rare, even in Japan.

The Japanese Terrier is a balanced, square dog, tri-coloured, with white predominating. Its ears are high set and fold forward. The coat is short, slick and fine. Its tail is docked.

The Miniature Fox Terrier is a small, fine, lightweight working terrier developed as a hunting dog and vermin router. It is known colloquially in its native Australia as the "Mini Foxie".

The breed was most likely developed from crosses between smaller Fox Terriers and Fox Terrier types and Manchester Terriers, and, later, crosses to other toy breeds such as the English Toy Terrier and Whippet. Hunters were seeking a smaller, speedy Fox Terrier that could be used for hunting smaller pests such as rats and rabbits. Although the origins of the breed are English, the breed was developed in and is endemic to Australia.

The Ratonero Bodeguero Andaluz (literally, the Andalusian Wine Cellars' Ratting Dog) is a Spanish terrier. It is believed to be descended from fox terriers crossed with other small breeds. This cross was probably during the XIX century, when many british businessmen stablished in Jerez to deal with Sherry. Its Spanish name reflects its main occupation: hunting rats hidden between Sherry barrels.

The Rat Terrier is an American dog breed with a rich and varied background as an all-around farm dog. Traditionally more of a type than a breed they share much ancestry with the tough little mixed breed dogs known as 'feists.'

Several private associations have maintained Rat Terriers registries for some decades, but more recently there have been movements to obtain breed recognition by the major canine organizations. Common throughout America on family farms in the 1920s and 30s, today they are generally considered a rare breed. Today's Rat Terrier is a handsome, intelligent, active little dog that is equally cherished as a farm helper and as a family pet.

The Tenterfield Terrier is a small, lightweight terrier akin to Miniature Fox Terriers, and Rat Terriers. The Tenterfield Terrier has English origins but, like dog breeds such as the Miniature Fox Terrier, the Australian Terrier, the Silky Terrier, and the Australian Cattle Dog, was developed uniquely in Australia.

As is so often the case, the origins of the breed are somewhat obscure. It is generally believed that smaller puppies from the litters of Fox Terriers were crossed with the progeny of other small breeds. Certainly, by the late 1800s a dog type known as the Little Foxie or the Miniature Fox Terrier (known colloquially as 'Mini Foxies') was well established in rural Australia. By the 1920s the dog was a fixture in urban households as well.