This paper discusses key elements underlying the fertility transition in sub-Saharan Africa with special attention to Kenya. Notwithstanding the contribution of family planning services and programs, we argue that a significant part of the sustained decline in fertility observed in Kenya, and probably other African countries, derives from fundamental shifts in the educational, economic, family and marriage institutions in the region. The changes occurring in these institutions maintain an independent effect on fertility. The contributions of marriage and education are particularly significant. The authors argue that, as these institutional changes become more manifest in other sub-Saharan African countries, similar effects will be observed in their fertility patterns, even in settings where the family planning environment remains weak.