For a long time, high-income countries tended to report a negative association between female educational attainment and childbearing. Belgium was among the first countries that seemed to witness the emergence of a positive educational gradient in female fertility. It has been argued that—alongside other contextual correlates—this trend reflects the increasing availability of work–family reconciliation policies from which especially highly educated people benefit. In contrast to the sizable body of literature assessing varying educational gradients in female fertility across countries, subnational regional variation has hitherto received little attention. As a result, we study the Belgian case using unique microdata covering all residents in 2002–2005. The main focus is on the relevance of between-municipality variation in economic conditions and childcare services for understanding variation in second birth hazards by educational attainment. We show that a considerable part of the municipal variation in the educational gradient in second birth hazards reflects a positive link between fertility and childcare provisions as well as wealth for highly educated women, contrasting with lower educated groups. Our findings suggest that institutional support for families is relevant but also incurs the risk of increased social polarisation.