This study investigates the relationship between security spending, human capital expenditure, and economic growth in Nigeria from 1999 to 2023 using the ARDL framework after unit root tests confirmed first-order integration of the variables. The bounds test confirms the existence of long-run cointegration. In the long run, security spending shows a negative effect on real GDP growth with a coefficient of-13.25 (p = 0.053), while human capital expenditure has a positive coefficient of 9.44 (p = 0.155). Foreign direct investment and inflation record positive coefficients of 1.49 and 3.50 respectively. Short-run results indicate that expenditure shocks are insignificant, but the error correction term is negative and highly significant at-0.958 (p = 0.000), implying about 96% adjustment to longrun equilibrium within one year. Administration-specific estimates reveal varying expenditure effects across the last four democratic regimes. The study concludes that public expenditure effects on growth in Nigeria are administration-specific, with human capital expenditure relatively more growth-enhancing than security spending.