Oh! What a Lovely War is a 1969 British epic comedy historical musical war film directed by Richard Attenborough, with an ensemble cast, including Maggie Smith, Dirk Bogarde, John Gielgud, John Mills, Kenneth More, Laurence Olivier, Jack Hawkins, Corin Redgrave, Michael Redgrave, Vanessa Redgrave, Ralph Richardson, Ian Holm, Paul Shelley, Malcolm McFee, Jean-Pierre Cassel, Nanette Newman, Edward Fox, Susannah York, John Clements, Phyllis Calvert and Maurice Roëves.

War film is a film genre concerned with warfare, typically about naval, air, or land battles, with combat scenes central to the drama. It has been strongly associated with the 20th century. The fateful nature of battle scenes means that war films often end with them. Themes explored include combat, survival and escape, camaraderie between soldiers, sacrifice, the futility and inhumanity of battle, the effects of war on society, and the moral and human issues raised by war. War films are often categorized by their milieu, such as the Korean War; the most popular subjects are the Second World War and the American Civil War. The stories told may be fiction, historical drama, or biographical. Critics have noted similarities between the Western and the war film.