How does the structure of a country's childcare market influence maternal employment? Childcare markets vary across countries, leading mothers to rely on various forms of care depending on what is available to them in both the public (state-provided) and private (non-state) childcare markets. Maternal employment is higher in countries that combine comprehensive childcare policies with an available and affordable private care market. When aspects of either the public or private market are lacking, the employment of mothers, and especially mothers with young children, is lower. This article proposes a fourfold classification scheme based on the type of 'penalty' that women experience in the labour market as mothers. It then links each penalty to distinct policy structures of childcare markets and shows that the four penalties are visible at both the country and individual level. By articulating how public and private care markets work in concert to shape maternal employment, this article adds to a literature that to date has focused primarily on the role of public childcare in reconciling work and family. (author abstract)