This paper addresses the causal impact of being raised in a sole-parent family on child well-being across the OECD. The question is answered by a cross-OECD meta-analysis and a literature review. There are widely varying rates of sole parenthood across the OECD. Rates of sole parenthood have generally been rising in the past few decades. Inevitably, countries with higher rates of sole parenthood are more concerned about the potential well-being effects on children. The reasons for sole parenthood include never having partnered, having separated and divorced, and being widowed. The composition of sole parents by these reasons varies widely across OECD countries. Views on the desirability of two-parent families for raising children are also divergent across the OECD.