When the First World War formally ended in late 1918 with an Allied victory, three vast and centuries-old land empires – the Ottoman, Habsburg and Romanov empires – vanished from the map. A fourth – the Hohenzollern empire – was significantly reduced in size, stripped of its overseas colonies and transformed into a parliamentary democracy. But the victorious Western European empires were not unaffected by the cataclysm of war either: throughout the "interwar" period, France fought back resistance to its imperial ambitions in Algeria, Syria, Indochina and Morocco, while British imperial rule was challenged in Ireland, Egypt, India, Iraq, Palestine, Afghanistan and Burma. This special issue takes John Gallagher’s classic “crisis of empire” conception of post-war Britain as a starting point to reflect more broadly on the notion of imperial crisis in the wake of the First World War. It includes contributions on the 1919 Egyptian revolution, wartime mobilisation in Britain’s African colonies and interwar policing in Palestine as well as essays on post-war violence in the defeated Ottoman, Habsburg and Romanov empires.