This article considers the issue of who should rebuild after war. Many leading advocates of the relevance of jus post bellum for Just War Theory adhere to the ‘Belligerents Rebuild Thesis’, which holds that those who have been involved with the fighting – such as the victor, just belligerent, unjust aggressor or humanitarian intervener – should be tasked with the responsibility to rebuild. By contrast, this article argues that there is a collective, international duty to rebuild that should be assigned primarily according to the agent's ability to rebuild – and not necessarily to the belligerents. The article also claims that, in contrast to the prevailing view, considerations of jus post bellum do not play any moral role in the justifiability of a war. Accordingly, defending the Belligerents Rebuild Thesis by invoking the alleged moral relevance of jus post bellum for Just War Theory is mistaken.