The Second World War was profoundly environmental as conflict transformed environments and human relationships with them. This chapter outlines various aspects of the war's environmental history through a focus on the relationship between militarized states, societies and environments during the period of totalizing warfare. Although research into war's environmental history has laid bare the complex environmental dimensions of warfare, few attempts have been made to consider the relationship between the Second World War's environmental history and totalizing war. The chapter argues that paying attention to the environment creates a fuller understanding of totalizing war between 1939 and 1945. Totalizing warfare led to the increased exploitation of natural resources, shifts in human-animal relations, and the militarization of vast swathes of national territories. Financial, labour and other constraints limited the total mobilization of the environment. Wartime nature protection efforts further limited the war's environmental repercussions, even if their overall impact was small.