A co-production is a joint venture between two or more different production companies for the purpose of film production, television production, video game development, and so on. In the case of an international co-production, production companies from different countries (typically two to three) are working together.

Co-production also refers to the way services are produced by their users, in some parts or entirely.

The journalist Mark Lawson identifies the first use of the term, in the context of radio production, in 1941, although the programme to which he refers, Children Calling Home, "Presented in collaboration between the CBC of Canada, NBC of the U.S.A., and the BBC, and broadcast simultaneously in all three countries", was first broadcast in December 1940.

Following the Second World War, American film companies were forbidden by the Marshall Plan to take their film profits in the form of foreign exchange out of European countries. As a result, several film companies started studios and production companies in nations such as the United Kingdom and Italy to use their "frozen funds".

To use these profits in England, film companies would set up production companies using the required amount of British film technicians and actors to qualify as British Productions in order to take advantage of the Eady Levy.

At the same time, American citizens working outside the country for 510 days during a period of 18 months would not be taxed on their earnings by the Internal Revenue Service. Though this scheme was developed for the aid of American humanitarian workers redeveloping nations destroyed in World War II, agents discovered that Hollywood actors, directors, and screenwriters would qualify for the tax break by working outside the United States for the same period.

International film co-production was very common in the 50s, 60s and 70s between Italian, Spanish and French production companies, as exemplified by most of the Spaghetti-western and sword and sandal movies being Spanish-Italian co-productions, typically directed by an Italian, played fifty-fifty by Spanish and Italian actors and shot in southern Spain landscapes. Due to the worldwide popularity of Hollywood stars, they would be used to guarantee a respectable audience around the world as well as the United States. The relatively low production costs and high box office return of these films often led to direct Hollywood investment to the non-American studios and producers such as Dino DeLaurentis. An example of such pan-European co-productions was Treasure Island (1972), a British-French-German-Italian-Spanish film, starring American filmmaker Orson Welles.

To qualify as an Italian film a film needed either an Italian director or cameraman plus at least two Italian featured players and an Italian film laboratory to process the film. Actor and director Mel Welles recalled that in the 1960s and 1970s the government of Spain would give producers funds based on the budget of the film whilst Italy would give producers funds based on the box office results of the film, however the government could interfere with production if they chose to.