This paper assesses whether fertility theories are still relevant in explaining fertility behaviour in the era of modernization of societies in sub-Saharan Africa over the past six decades. The paper particularly focuses on five classical fertility theories: Child Survival Hypothesis, Intergenerational Flow of Wealth, Relative Income Hypothesis, Demand and Supply Framework of Fertility and Value of Children Theory. A rapid scoping review of five classical fertility theories and empirical literature on fertility in sub-Saharan Africa and other developing regions was done using data sources such as PubMed, Scopus, ScienceDirect, EBSCO, MEDLINE and JSTOR. Three arguments are made. First, the theories of fertility provide some form of understanding of how traditional values and institutions encourage high fertility behaviour in traditional African societies. Second, even though some fertility theories predicted a fall in fertility with the emergence of modernity, empirical research and statistical evidence showed no significant reduction in general fertility levels. Last, empirical studies in the African subregion have acknowledged the presence of such modern institutions and have found that these institutions have influenced the fertility decisions of many within the subregion. What is theoretically expected to occur in terms of fertility reduction is moderate. In effect, traditional values still play a vital role in fertility behaviour and are deeply entrenched in fertility decisions in the subregion.