In our society that values men over women and youth over old age, sexism and ageism intersect to erode women's status more rapidly and severely than men's. However, limited attention is given to women's responses to their devaluation, particularly collective efforts to either resist or accommodate dominant beliefs about ageing women. We examine membership in the Red Hat Society, an international organisation for middle-aged and older women, as a response to gendered ageism. Drawing on data from semi-structured interviews with members (N = 52), our analysis focuses on the group's ‘performance of girlhood’, which involves adopting children's social roles, dressing up and playing. We examine its resonance with a dominant cultural metaphor for old age as ‘second childhood’, illustrating how it not only provides opportunities for resistance to gendered ageism but also contributes to its entrenchment. The behaviours constitute a performative act that resists gendered ageism by increasing ageing women's visibility and asserting their right to leisure. However, its accommodative features reproduce inequality by valuing youth over old age and depicting older women as girls engaging in frivolous activities, which can be seen as obstructing social change.