This study assesses how changes in unmet need for family planning have contributed to contemporary fertility declines, and the implications of this historical record for further fertility decline, especially in sub-Saharan Africa. We examine joint trends at the national level in fertility, unintended fertility, and unmet need. We bring unintended fertility into the analysis because the underlying rationale for reducing unmet need is to avert unintended pregnancies and births. The association over time between unmet need and fertility is investigated using survey data from 45 countries in Africa, Asia, and Latin America and the Caribbean from the mid-1970s to the present. The empirical analysis finds that reduction in unmet need, especially unmet need for limiting, is strongly associated with fertility decline in Latin America and the Caribbean and in Asia and North Africa. Fertility decline in sub-Saharan Africa is weakly associated with trends in unmet need (and satisfaction of demand). We propose that the stark regional difference is due to measurement problems and to the fundamentally different character of fertility decline in sub-Saharan Africa, itself reflective of basic differences in pretransition reproductive regimes.