The breed known today as the Norwich Terrier was recognized in England around the end of the 19th century. Its origin is still debated, with some experts claiming it descended from small red or Irish terriers, while others sustain that other breeds, such as the Trumpington, Yorkshire, Skye, English Smooth, Scotch, Dandie Dinmont, Bull and Crossed Scotch, probably contributed to varying degrees. When it was officially recognized by the Kennel Club in 1932, two varieties were registered, the Prick Ear and the Drop Ear. After recognition, a great deal of debate arose as to which type of ear carriage should be considered "superior" and awarded in the show ring; indeed, breeders were so attached to one or the other type of ear that there were very few crosses between the varieties. Finally, the British Kennel Club split the varieties into two officially recognized breeds, the Norwich and the Norfolk, in 1964, with the Canadian and American Kennel Clubs following suit in 1979.

So what are the differences between the two breeds? Was the Kennel Club right in splitting them into two distinct groups? There will be some breeders that tell you that the two breeds are exactly the same, though these breeders often just breed one or the other type of terrier; breeders, as well as owners, that have had experience with both dogs will fervently claim that they are quite different. The most obvious difference, and the one used to immediately tell the two breeds apart, is ear carriage, or the way the dog holds its ears. The Norwich terrier has prick ears, or ears that stand up, seemingly at alert, while the Norfolk has drop ears, or ears that seem to be folded over. A quick way to remember this difference is to remember that the Norwich has pointy ears like the hat of a wich (spelling mistake intended), while the Norfolk has folded ears.

There are other physical differences between the two terriers as well. The Norwich on average have moderately smaller feet than the Norfolk and they seem a bit heavier in proportion to their size. Among their characteristics are a shorter back coupling and a less pronounced front and rear angulation when compared to their cousins, so they give the appearance of being somewhat more short backed. Norfolk terriers are less "wiry" than the Norwich and some breeders claim that their tails wag, while the movement of Norwich tails resembles more of a quiver. As far as barks go, that of the Norwich terrier seems to be lower pitched. There is also a difference in breeding ability, as Norwich tend to give problems and more often than not must be born through cesarean section; Norfolk do not seem to have any problems.

Personality differences also exist between the two breeds. The prey instinct is much more present in the Norfolk and they are very independent dogs with a high degree of concentration, to the point where many have reported seeing Norfolk terriers intently watching TV. Norfolk also tend to display jealous behavior much more often than Norwich. Norwich can easily adapt to a variety of surroundings, even urban, and they are more attached to their human companions, depending more on human affection.