Poverty among smallholder farmers in sub-Saharan Africa has been associated with low agricultural productivity emanating from gender yield gaps among other factors. Using data collected from smallholder groundnut producers in Nigeria, we analyzed the gender yield gap by applying the exogenous switching regression (ESR) model and Oaxaca–Blinder (OB) decomposition framework. Results from the two complementary approaches showed a significant gender yield gap in favor of male headed households (MHHs). The main and significant source of the gap was differences in resources/endowments. We found that involving female headed households (FHHs) in prerequisite yield augmenting activities like technology validation trials, testing, and demonstrations is critical in closing the existing yield gap.