Introduction: Homosexuality and labour historyThe overlap between the history of homosexuality and social attitudes towards it may seem to be somewhat removed from the dynamics of labour movements. The reception of understandings and perceptions about homosexuality in trades unions and political parties, however, are but a microcosm of broader attitudes in society generally and even though they may take on a particular hue in these milieus, they provide evidence of the lines of tension existing within the rejection/tolerance dyad that informs such practices. Although we may perhaps anticipate greater tolerance of alternative or non-mainstream sexualities and expressions of gender within 'progressive' labour movements across the globe, this may have more to do with the historian's subjective expectations than reality. Such positive attitudes were, in the past, and, are in the present, often absent and, in some cases, opposition to homosexuality within labour movements has been marked. The acceptance or otherwise of homosexuality as an expression of greater sexual freedom relied principally on contextual factors such as movements' relationships with understandings of modernity, the power of science to explain social phenomena and the reception of secularist ideas.While much has now been written on gender questions within labour movements beyond the mere 'incorporation' of women into movement history to embrace the relations between men and women within them, 1 the question of non-reproductive sexuality, whether 'heterosexual' or 'homosexual', 2 and the ways in which this was perceived in labour movements, continues to constitute an undeveloped field. This is certainly the case for Portugal and this article seeks