Although infertility causes women considerable grief, social stigma, and economic deprivation, scholars have paid little attention to infertility's definitions that may depart from the standard Western usage and how such definitions influence the way women experience the condition. This article, by listening to individual women's experiences of infertility in two Nigerian communities, examines these definitions and differentiates between culturally salient categories of infertility. In distinguishing between different kinds of childless women and those with low fertility, we intend to enhance understandings of infertility by considering women's subjective understandings of the condition and thus moving beyond the current medical definition. By comparing women's experiences in two different ethnic groups in Nigeria, we show how distinct forms of kinship structures and social organizations shape the ways low fertility is defined, managed, and experienced.