Reliance on grandparents for children’s informal care is very popular in Australia. Yet little is known about the gendered dynamics of grandparental care. This study, based on 3000 grandparents taking part in Wave 7 of the Household, Income and Labour Dynamics Survey (HILDA) and 14 in-depth interviews with grandparents, reveals that gendered inequalities associated with providing childcare significantly influence the lives of older Australians, particularly grandmothers. Grandmothers doing grandchildcare experience greater dissatisfaction with free time and more than their fair share of domestic labour compared to grandfathers. Gendered meanings and practices of grandchildcare evident in interviews position grandmothers as nurturing, coordinators of care. Grandfathers are somewhat influenced by notions of ‘involved fathering’ as they are emotionally engaged in children’s recreational activities, yet are relatively free to opt in and out of caring labour. We conclude that the gendered organisation of grandchildcare is consistent with a dominant maternalist culture in Australia.