This study examines the short-run and long-run effects of population growth and unemployment on economic growth in Nigeria using annual time-series data. Employing the Autoregressive Distributed Lag (ARDL) approach, with government expenditure and per capita income included as control variables, the study accounts for mixed orders of integration and dynamic adjustments. The bounds test confirms the existence of a long-run cointegrating relationship among the variables. The short-run results reveal that unemployment has a negative and statistically significant effect on real GDP growth, while population growth exerts a negative but insignificant influence. Government expenditure and per capita income show positive but insignificant effects in the short run. In the long run, population growth emerges as a positive and significant driver of economic growth, suggesting the presence of a potential demographic dividend, whereas unemployment remains negative and statistically significant, indicating persistent labour market inefficiencies. The control variables maintain positive but insignificant effects in the long run. These findings imply that Nigeria’s demographic expansion can support economic growth only when accompanied by effective employment creation and labour market absorption. The study therefore underscores the importance of employment-centered growth strategies, human capital development, and efficient public expenditure in harnessing population growth for sustainable economic development.