In this paper, we study the effects of a Dutch childcare reform that tightened access to subsidised childcare on gender inequality in the labour market. Before 2011, as long as both parents were working, Dutch families were entitled to subsidised childcare for children under age 4 with unconstrained maximum hours. In 2012, a childcare reform restricted the maximum hours of subsidised childcare to 140% of hours worked of the least working parent. We employ a triple-difference strategy that combines variation in exposure to the 2012 reform across time and families with and without a toddler-age child. We find the reform has aggravated gender inequality in labour supply within the household. Restricting access to subsidized childcare led to a sizable 11.5 percentage point reduction in the labour force attachment for mothers from the affected families, but had much smaller and insignificant effects for fathers.