For affiliates in the corporate world, see affiliate (commerce).
In broadcasting, a network affiliate (or affiliated station) is a local broadcaster which carries some or all of the programme line-up of a television or radio network but is owned by someone other than the owner of the network.
In most American commercial television networks, a few large stations in key markets are stations that are owned-and-operated (O&O) by the network itself, while smaller markets are served by affiliates. For instance, New York broadcasters WCBS-TV, WNBC, WABC-TV and WNET (PBS) are not affiliates (they are network-owned, or in PBS's case, a "PBS member station" as that network's structure differs from the commercial O&O + affiliates model). In Canada, most television stations, regardless of market size, are now O&Os of their respective networks, with only a few true affiliates remaining. The Canadian Broadcasting Corporation originally relied on a large number of privately-owned affiliates to disseminate its radio and television programming. However, since the 1960s, most of the CBC Television affiliates have been replaced by network owned and operated stations or retransmitters. CBC Radio stations are now entirely O&O.
While network-owned stations will normally carry the full programming schedule of the originating network, an affiliate is independently-owned and typically under no obligation to do so. Affiliated stations often buy supplementary programming from another source, such as a syndicator or another television network which does not have coverage in the station's broadcast area, in addition to the programming they carry from their primary network affiliation. In some smaller markets, a station may even be simultaneously listed as an affiliate of two networks.