Backyard breeding is a term used to describe irresponsible breeding of animals. Often this is due to ignorance or nelect where a dog or cat accidentally becomes pregnant because the owner has failed to have them desexed. In other cases animals are deliberately bred so the animals can be sold to pet shops or new owners. When such breeding is carried out on a large scale, the term puppy mill or puppy farm is used.

What distinguishes backyard breeders from responsible breeders are the standards that the breeder meets and whether there is a known demand for puppies before they are bred.

Backyard breeding contributes to the overpopulation of animals of animals in the community. Uncontrolled breeding and overpopulation ultimately leads to the euthanasia of  fit and healthy unwanted animals every year.