We investigate the gap in math and science achievement of third- and fourth-graders who live with a single parent versus those who live with two parents in 11 countries. The United States and New Zealand rank last among the countries we compare in terms of the equality of achievement between children from single-parent families and those from two-parent homes. Following a multilevel analysis, we find single parenthood to be less detrimental when family policies equalize resources between single- and two-parent families. In addition, the single- and two-parent achievement gap is greater in countries where single-parent families are more prevalent. We conclude that national family policies can offset the negative academic outcomes of single parenthood.