The term anti-war film is sometimes used to describe films which bring to the viewer the pain and horror of war, often from a political or ideological perspective.

An early notable war film is Charlie Chaplin's Shoulder Arms made in 1918. The film set a style for war films to come and it can be considered the first comedy about war in film history. Films made in the years following World War I tended to emphasise the horror or futility of warfare, most notably The Big Parade (1925) and What Price Glory? (1926). With the sound era, films like All Quiet on the Western Front (1930), Howard Hawks' Road to Glory (1936) and Grand Illusion (1937), focused on the futility of war for non-American soldiers whilst Hollywood produced American soldiers featuring in World War I comedies such as Buster Keaton's Doughboys (1930) and Wheeler & Woolsey's Half Shot at Sunrise (1930), or exciting tales of the U.S. Marine Corps putting down rebellions in Central America, China, and the Pacific Islands in films like Frank Capra's Flight (1930), The Leathernecks Have Landed (1936) and Tell it to the Marines (1926 film). Other films focused on the drama inherent in the new technology and fading chivalry of aerial combat in films such as Wings (1927), Hell's Angels (1930) and The Dawn Patrol (1930 and 1938 versions).

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 Noel Coward's 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).

The Selective Training and Service Act of 1940 was passed by the United States Congress on September 16, 1940, becoming the first peacetime conscription in United States history. Hollywood reflected the interest of the American public in Conscription in the United States by having nearly every film studio bring out a military film comedy in 1941 with their resident comedian(s). Universal Pictures' Abbott and Costello came out with the first feature film on the subject Buck Privates and followed it with the team In The Navy and in the United States Army Air Corps to Keep 'Em Flying. Paramount Pictures' Bob Hope was Caught In The Draft, Warner Brothers told Phil Silvers and Jimmy Durante You're In The Army Now, Columbia Pictures put Fred Astaire in the army declaring You'll Never Get Rich, Hal Roach gave his new comedy team of William Tracy and Joe Sawyer Tanks a Million and 20th Century Fox had the former Hal Roach team of Laurel & Hardy going Great Guns. The minor studios such as Republic Pictures made Bob Crosby and Eddie Foy Jr Rookies on Parade and Monogram Pictures enlisted Nat Pendleton as Top Sergeant Mulligan. However, the first comedians to hit the screen in an army comedy were The Three Stooges as Boobs in Arms.

Serious 1941 films involving training for war included U.S. Cavalry in MGM's The Bugle Sounds, RKO's Parachute Battalion, Paramount Pictures I Wanted Wings and Warner Brothers' Dive Bomber. 20th Century Fox made the last pre-war military film about the U.S. Marine Corps To The Shores of Tripoli. When the Pearl Harbor attack occurred the studio reshot the ending to have John Payne reenlist in the Corps and march off with the Marines whilst his father implores him to 'Get a Jap for me'.

Prior to Pearl Harbor, Warner Brothers warned of Confessions of a Nazi Spy whilst PRC told of Hitler, Beast of Berlin. A metaphor for America was Gary Cooper as the real life Sergeant York who went from hillbilly hell-raiser, to pacifist, to a draftee comparing the Bible to the History of the United States and deciding that his marksmanship against the Germans was righteous.

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 and its Communist Party). 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 Guadalcanal Diary (film) (1943), Thirty Seconds Over Tokyo (1944) and They Were Expendable (1945).

The years after World War II brought a large number of mostly patriotic war films, which used the war as a backdrop for dramas and adventure stories. Many films made in Britain drew on true stories, such as The Dam Busters (1954), Dunkirk (1958), Reach for the Sky (1956) telling the life of Douglas Bader and Sink the Bismarck! (1960). The immediate aftermath of the war in Hollywood avoided the action film and delved into problems experienced by the returning veterans, turning out a number of high quality movies that included The Best Years of Our Lives (1946), Battleground (1949), Home of the Brave (1949), Command Decision (1948), and Twelve O'Clock High (1949). The latter two examined the psychological effects of combat and the stresses of command.