How do members of the general public come to regard some uses of violence as legitimate and others as illegitimate? And how do they learn to use widely recognised normative principles in doing so such as those encapsulated in the laws of war and debated by just war theorists? This article argues that popular cinema is likely to be a major source of influence especially through a subgenre that I call ‘Just War Cinema’. Since the 1950s, many films have addressed the moral drama at the centre of contemporary Just War Theory through the figure of the enemy in the Second World War, offering often explicit and sophisticated treatments of the relationship between the jus ad bellum and the jus in bello that anticipate or echo the arguments of philosophers. But whereas Cold War-era films may have supported Just War Theory’s ambitions to shape public understanding, a strongly revisionary tendency in Just War Cinema since the late 1990s is just as likely to thwart them. The potential of Just War Cinema to vitiate efforts to shape wider attitudes is a matter that both moral philosophers and those concerned with disseminating the law of war ought to pay close attention to.