Hybridization is the cross-breeding of plants or animals, between different species to produce offspring, known as hybrids, that differ in genetically determined traits; it is commonly the result of human intervention. Changes in climate or in the environment of an organism may give rise to natural hybridization, but usually humans use specialized techniques to produce hybrids that may be hardier or more resistant to disease than the original forms, or more economical.

Hybridization may also refer to the base pairing of two single strands of DNA or RNA.