Elderly people with functional limitations are predominantly cared for by family members. Women – spouses and daughters – provide most of this care work. In principle, gender inequality in intergenerational care may have three causes: first, daughters and sons have different resources to provide care; second, daughters and sons respond differently to the same resources; third, welfare state programmes and cultural norms affect daughters and sons differently. In this paper, we address the empirical question whether these three assumed causes are in fact responsible for gender differences in intergenerational care. The empirical analyses, based on the Survey of Health, Ageing and Retirement in Europe (SHARE), reveal that parents in need are in fact more likely to receive care from daughters than from sons. Daughters are more responsive to the needs of their parents than sons and respond differently to the same resources. Gender inequality is highest in countries with a high level of intergenerational care, high public spending on old-age cash-benefits, a low provision of professional care services, high family obligation norms and a high level of gendered division of labour. Welfare state programmes reduce or increase gender inequality in intergenerational care by reducing or increasing the engagement of daughters in intergenerational care. In general, care-giving by sons is hardly influenced by social care policies.