Drawing on research conducted over the last 20 years, mostly in the United Kingdom and France, but also in the USA, Caribbean and Hungary, this paper examines the evolution of women’s union participation, in different organisational and occupational contexts, with varying degrees of skill, precariousness and feminisation. Exploring how feminisation processes manifest themselves at different levels of activism, it emphasises both importance of contextualising unions’ feminisation processes within specific inequality regimes and the need to adopt an intersectional perspective on women’s union participation.