In recent years there has been increasing policy focus on keeping mature-age people engaged in the labour market. At the same time, grandparents play an important role as regular child-care providers for many families. Yet, little research has explored how grandparents negotiate these dual, often competing demands of paid employment and intergenerational care. Drawing on focus groups with 23 grandparents and an online survey of 209 grandparents providing regular child care for their grandchildren in Australia, this paper addresses this gap in the literature by examining how Australian grandparents experience and negotiate competing responsibilities as older workers and intergenerational care providers. The paper draws on the concept of gendered moral rationalities to examine the way in which grandparents’ decisions about participation in paid work are deeply embedded in idealised forms of parenting and grandparenting that are highly gendered. The paper suggests that, as the rate of both maternal and mature-age participation in the paid labour market continues to rise, inadequate attention is being paid to how time spent undertaking unpaid care is compressed, reorganised and redistributed across genders and generations as a result.