Despite decades of policy attention, financial exclusion remains among the most binding constraints on economic growth in sub-Saharan Africa. This study examines the relationship between financial inclusion — specifically access to credit and mobile banking — and economic growth in Nigeria over the period 1995–2022. Using an ordinary least squares (OLS) cross-sectional time-series regression framework, the study controls for demographic factors (DF), macroeconomic factors (MF), institutional factors (INSF), global factors (GF), and infrastructural factors (INFF). The empirical results confirm that both credit access (CRED: β = 0.264, p < 0.05) and mobile banking (MOB: β = 0.351, p < 0.01) exert statistically significant positive effects on GDP growth, even after introducing the full suite of control variables. Inflation (INF: β = −0.098, p < 0.01) and population growth (POPG: β = −0.811, p < 0.05) exert significant negative effects, while regulatory quality (REGQ: β = 1.341, p < 0.05) and internet penetration (INTP: β = 0.144, p < 0.05) amplify the growth-enhancing effects of inclusion. The findings are robust to heteroskedasticity-consistent standard errors and pass a battery of post-estimation diagnostics. The study contributes to knowledge by providing one of the most comprehensive multivariate analyses of financial inclusion and growth in Nigeria, integrating dimensions of the institutional and infrastructural environment that are routinely omitted from existing country-level analyses. Policy implications are discussed for the Central Bank of Nigeria, the Securities and Exchange Commission, and international development partners.