This article examines the effect of total war on inequalities in pay in munitions industries in Britain during World War II. I present new data derived from Ministry of Labour monthly reports of changes in wage-rates, which allows for a systematic analysis of pay inequality by skill category and by gender and age. I also investigate changes in earnings equality using data derived from Earnings and Hours Enquiries and from records of the National Arbitration Tribunal. I conclude that pay differentials – defined by skill, gender or age – narrowed considerably during World War II. For men, the War represented an accentuation of a trend towards greater levelling that commenced in the later part of the 1930s and continued in the immediate postwar years. This was not the case for women workers. During the War years gender pay inequality in munitions industries was substantially reduced, but some of these gains were eroded with the coming of peace and demobilisation. Wartime labour policy was directed toward the deskilling of manufacturing work and this was coupled with both a significant expansion of unionisation (especially among unskilled workers) and institutional and legal changes that strengthened the bargaining position of trade unions. These factors suggest that institution factors worked in conjunction with labour demand effects to reduce pay inequality in those industries crucial for the war effort.