Pre-school education and care (PSEC) is often claimed as a ‘win-win’ policy which simultaneously enhances both economic competitiveness and social cohesion. High levels of PSEC are said to raise living standards by increasing female employment rates and improving young people’s skills and to mitigate inequalities by reducing social gaps in learning outcomes. Much of the evidence for this rests on analysis of data for a small number of countries. In this paper we test the claims using cross-national time series data for a large number of OECD countries. The analysis of determinants of employment rates, using a variety of controls, does confirm the association between PSEC participation levels and female employment rates. However, the cross-national analysis does not support the argument that raising aggregate levels of PSEC participation necessarily reduces social gaps in attainment at 15 years of age. Participation in PSEC increases educational performance at 15 by similar amounts for children of all social groups in most countries. Social gaps in performance at 15 may only be mitigated by high levels of PSEC provision where children from less advantaged families get more – or better quality – provision. The recently announced Department for Education plan to extend free provision of PSEC for fifteen hours a week to two-year-old children from disadvantaged families (i.e. in care or qualifying for free school meals) therefore points in the right direction. However, it remains to be seen whether this will bias participation towards this group sufficiently to reduce inequalities in learning outcomes.