Scientific models depicting the evolution of human (or perhaps hominin) religion have to be embedded in concordant explanations of biological and cultural evolution. They fall into three categories: (1) Evolutionary biology is applied to culture, assuming that cultural traits evolve following a pattern similar to biological evolution; (2) culture is regarded as a key influence in human evolution, leading to concepts of gene-culture coevolution; and (3) culture and religion are seen as emerging from cognitive evolution. In this chapter, the impact of the current state of evolutionary biology on theories of religion’s evolution is considered. Possible gaps in knowledge are discussed, both in methodology and in the proposals of theories using a selectionist approach. The conclusion is that cultural evolution, with religion as a subsystem, has to be regarded as a process by which a complex, multilayer system of behavioral and cognitive features adapts, changes and expands, from the prehistoric beginnings of the hominins to known history. In such a system, characteristics emerge on each level, which cannot be completely reduced to the characteristics of lower levels. Descriptions and explanations of religion’s evolution have to conceive multilevel interactions of biological and cultural dynamics. Possible venues are considered to integrate biological, social and cultural aspects into such multidimensional models of religious evolution.