This paper explores the linkages at the family level between sustained high fertility and children's schooling in Ghana, in the context of a constrained economic environment and rising school fees. The unique feature of the paper is its exploration of the operational significance of alternative definitions of “sib size” - the number of “same-mother” siblings and “same-father” siblings - in relation to enrolment, grade attainment, and school drop-out for boys and girls of primary and secondary school age. The analysis is based on the first wave of the Ghana Living Standards Measurement Survey (GLSS) data, collected in 1987-88. The results of the statistical analysis lead to the conclusion that the co-existence of high fertility, rising school costs, and economic reversals is having a negative impact on the education of girls, in terms of drop-out rates and grade attainment. Some of the costs of high fertility are borne by older siblings (particularly girls) rather than by parents, with the result that children from larger families experience greater inequality between themselves and their siblings by sex and birth order. Because fathers have more children on average than mothers, the inequality between their children appears to be even greater than between mothers' children, particularly given the importance of fathers' role in the payment of school fees. The paper concludes that the greatest cost for children in Ghana of sustained high fertility is likely to be the reinforcement of traditional sex roles, largely a product of high fertility in the past.