The campaign for equal pay marked an important milestone in the transformation of the Australian Insurance Staffs’ Federation. Much discussion of equal pay has focussed on ‘gender solidarity’ between male workers and employers, or a conflict of interest between male and female workers. This article argues that the equal pay campaign united male and female insurance workers against their employers on a class basis. The course of the campaign illustrates the benefits that workers gained from uniting in this way. The union itself was not only larger as a result of the campaign, but also commanded more respect from management. This growth, and the respect that accompanied it, came from the involvement of wide layers of members in unprecedentedly militant industrial action. The fact that so many of those members were women, and that the issue which galvanised the union was such a direct challenge to sexist attitudes, meant a transformation in the way in which women were seen both inside the AISF and more generally. This case study, using written sources and interviews with participants, outlines the actions undertaken by the Australian insurance industry union to campaign for equal pay for women in 1973-75. It seeks to provide an analysis of the actual struggles that led to improvements in women’s wages.1 The article also attempts to use this empirical material to throw light on a theoretical argument: can the campaign be explained and understood by reference to class or to gender interests?