The celebration of Empire Day in Britain was of greater significance than previous research has suggested. This article disproves the misconception that the festival was restricted in the main to a constituency of schoolchildren. The celebrations had a far wider effect on diverse communities; in many cases the ritual celebration of the British Empire traversed class boundaries and helped to sustain traditional social hierarchies. In the immediate aftermath of the First World War, when unrestrained jingoism became inappropriate, Empire Day retained its hegemonic potency by amalgamating the emerging traditions of sombre commemoration into the repertoire of imperial festivity. Empire Day, although remaining popular during the interwar period, became an arena of passionate contestation. The Conservative party and other groups adopted Empire Day as a vehicle for anti-socialist propaganda, whilst the communist party exploited it as an opportunity to attack British imperialism. Other protests came from local Labour groups and pacifist dissenters. The overt politicization of Empire Day severely disrupted its hegemonic function and the political battles fought over the form and purpose of the celebrations made it difficult to uphold the notion that the festival was merely a benign tribute to a legitimate and natural state of affairs.