An affiliate is a relationship between two businesses where one firm owns a minority interest in the other organization. The concept can also describe the relationship between two subsidiaries that are owned by the same parent company. Affiliation can also exist when two firms have interlocking directorships.

In electronic commerce, an affiliate is a website that offers third party goods and services for sale on its website, where the third party fulfills orders placed on the website and pays the website owner a commission in exchange.