In the 1980s and 1990s, a significant number of rank-and-file trade union activists in Canada became actively engaged in various forms of international labour solidarity. This activity, the end of the Cold War and the increasing impacts of neo-liberal globalisation combined to spark hopes for greatly expanding practices of labour transnationalism. This vision of transnationalising trade union organisation has not materialised and, in fact, inside Canadian unions there has been declining faith in the possibilities of building transnational solidarity. Starting with an analysis of the dominant dichotomies underlying the literature on labour transnationalism, I suggest that stepping outside these dichotomies can provide a different way of assessing the role of transnational labour solidarity within broader struggles for workers’ justice. In this article, drawing upon the case of transnational political solidarities built by workers inside Canadian unions in the 1980s and 1990s, I argue that assessing transnational practices with a longer view to class formation and the goals of workers’ emancipation can help to expand conceptions of what constitutes successful transnational practice. Such a reassessment of the role of labour transnationalism is particularly timely in the current context of right-wing populism.