An interspecies friendship is a nonsexual bond that is formed between animals of different species. Numerous cases of interspecies friendships among wild and domesticated animals have been reported and documented with photography and video. Domestication of animals has led to interspecies friendships between species that would never naturally exist together. In many cases of interspecies friendship, the species are not normally seen together, and sometimes, one is of a species that ordinarily preys on the other in nature.

Human–canine bonding is the relationship between dogs and humans. This relationship can be traced back to at least 15,000 years ago, to the Bonn-Oberkassel dog, who was found buried alongside two humans. For centuries, dogs have been considered man's best friend. This is most evident in western countries, such as the United States, where over 48% of households have a pet dog.