By 1939 expectations in France of a major colonial contribution to the impending war effort were high. The idea of le salut par l'empire, literally ‘salvation by the empire’, even gained some currency among ministers, officials, and the wider public. This article examines the nature of the economic and military demands imposed on France's major overseas territories in the immediate pre-war years, focusing on the two pre-eminent colonial groupings of the empire: French North Africa and the Indochina federation. It suggests that colonial economies and working populations were poorly placed to meet French expectations of them. The colonies were severely affected by the economic depression of the early 1930s and slower to recover than metropolitan France. Structural economic difficulties imposed limits on the mobilization of colonial resources, a problem made appreciably worse by the earlier disagreements among ministers, colonial officials, and business leaders over the merits of colonial industrialization. The reversal of planned social and constitutional reforms after 1936 added to the political volatility and social divisions of colonial societies as war drew near.