1940s

The first popular war films during the Second World War came from Britain and Germany and were often documentary or semi-documentary in nature. Examples include The Lion Has Wings and Target for Tonight (British) and Sieg im Westen (German).

By the early 1940s, the British film industry began to combine documentary techniques with fictional stories in films like In Which We Serve (1942), Millions Like Us (1943) and The Way Ahead (1944). Others used the medium of the fiction film to carry a propaganda message; about the need for vigilance (Went the Day Well?) or to avoid "careless talk" (The Next of Kin).

After the United States entered the war in 1941 Hollywood began to mass-produce war films. Many of the American dramatic war films in the early 1940s were designed to celebrate American unity and demonize "the enemy." One of the conventions of the genre that developed during the period was of a cross-section of the American people who come together with a common purpose for the good of the country, i.e. the need for mobilization. The American industry also produced films designed to extol the heroics of America's allies, such as Mrs Miniver (about a British family on the home front), Edge of Darkness (Norwegian resistance fighters) and The North Star (the Soviet Union). Towards the end of the war popular books became the source of films of higher quality and more serious tone, extoling more long-term values, including Thirty Seconds Over Tokyo (1944) and They Were Expendable (1945).