The Jack russell terrier and parson russell terrier are different breeds, but both originate in Britain. The parson russell was bred to be a tough hunting dog, and to look almost identical to how fox terriers looked roughly 100 years ago. The jack russell has always been more of a farm dog, but is also very popular around the world as a companion dog. In Australia, 2000 jack russell terriers were registered in 1998.

The jack russell should be a typical terrier - active, agile and strong. The head should be slightly triangular, with the muzzle slightly shorter than the skull, very powerful jaws and clearly marked stop. The eyes should have an intense expression. The ears should be V-shaped and hanging or slightly raised. The neck is not too long but carried high. The body should be rectangular, with the chest as deep as the legs are long. The frontlegs should be as straight as possible, with excellent boning. The tail should be as straight as possible. The coat can be smooth, wire or broken.