This study examines the impact of financial deepening and sustainable energy supply on domestic investment in West African countries. The data for the study range from 1990 to 2020 and were sourced from the World Development Indicator database. We used the cross-sectional autoregressive distributed lag (CS-ARDL) estimator for the analysis. Empirical findings showed that credit to the private sector significantly impacts domestic investment in West Africa. It was also revealed that access to electricity significantly impacts domestic investment in West Africa. This demonstrates that funding for the private sector and adequate power generation improve the investment in any economy. The study concludes that financial deepening has a significant impact on domestic investment. The study therefore recommends that the management of banks should be encouraged to pursue policies that will deepen the efficient allocation of financial services for domestic investment in the region.