Religion occupies a central position in the social, political, and cultural life of Sub-Saharan Africa. While existing scholarship has examined its moral authority, social capital, and political influence, its economic role remains marginal in mainstream development analysis. This paper reconceptualises religious institutions as economic institutions that mobilise resources, accumulate capital, shape labour relations, and influence household and national development outcomes. Drawing on political economy and institutional economics, the study introduces the Religious Economic Complex (REC) framework, which explains how faith, trust, and cultural legitimacy are transformed into sustained economic power. Using a mixed-methods approach combining household survey data (N ≈ 45,000), cross-country development indicators, and qualitative case studies from Nigeria, Ghana, Kenya, and South Africa, the paper demonstrates that religious institutions operate as quasi-market actors largely outside formal regulatory oversight. The findings indicate that religious economic activity is associated with significant opportunity costs for households and is linked to long-term development trajectories, particularly industrialisation and productive investment. By repositioning religion at the centre of economic analysis, the paper contributes a novel institutional perspective to development studies and highlights the importance of incorporating religious economic activity into development frameworks.