The main historiographical accounts of World War II in North Africa focus on conventional warfare and inter-imperial rivalry, thus overlooking a significant rise of colonial violence behind the frontline throughout the region. My paper challenges this dominant perspective through an extensive study of British, Italian, and French diplomatic, military, and colonial sources on Tunisia and Libya between 1940 and 1943. The sources are used to compare the impact of the war on colonial relations in both French and Italian colonial possessions, and to highlight trans-imperial connections between them. The findings show that both in Libya and Tunisia the war exacerbated tensions between European settlers and Arabs, leading to open rebellion and intercommunal violence, particularly in the countryside. Between 1940 and 1943 both Rome and Vichy mobilized and repressed North Africans to serve war goals, reinforce imperial loyalty and defend racial hierarchies. At the same time, both Libyans and Tunisians exploited inter-imperial conflict and the temporary weakness of European powers to act on an anti-colonial agenda that pre-existed the war. They challenged colonial powers through low-intensity guerrilla, the targeting of agricultural settlements, and everyday resistance to settlers and colonial authorities. The ensuing repressive wave from settlers and colonial authorities entailed anti-guerrilla warfare, paramilitary violence, and collective punishment. As a result, the North African imperial space underwent a radical change: pressure from both anti-colonial resistance and inter-imperial conflict forced Fascist Italy out of Libya, while in French Tunisia racial resentment and political radicalization paved the way for decolonization. The contribution of this paper is threefold: it emphasizes the long-term, regional dimension of colonial violence and decolonization in North Africa; it revaluates the agency of North Africans behind the frontline; finally, it sheds light on the nature of the New World Order from a colonial standpoint.