In biology, mating is the pairing of opposite-sex or hermaphroditic organisms for copulation. In social animals, it also includes the raising of their offspring. Copulation is the union of the sex organs of two sexually reproducing animals for insemination and subsequent internal fertilization. The two individuals may be of opposite sexes or hermaphroditic, as is the case with, for example, snails.

For animals, mating methods include random mating, disassortative mating, assortative mating, or a mating pool. In some birds, it includes such behaviours as nest-building and feeding offspring. The human practice of mating domesticated animals and of artificially inseminating them is part of animal husbandry.