This paper presents a detailed empirical analysis of the dynamics of fiscal policy by evaluating the impact of government expenditure and public debt on economic growth in Tanzania from 1990 to 2021, with data extracted from the World Development Indicators (WDI). The paper employed the Vector Error Correction Model (VECM) and Granger causality techniques. The paper presents the findings of a statistically insignificant unidirectional relationship between public expenditure and economic growth. It attributes the negative coefficient of government expenditure in the long run to the prevalence of recurrent expenditure over developmental expenditure, potentially acting as a hindrance to economic growth in Tanzania. Furthermore, the paper suggests a statistically significant and positive long-term relationship between public debt and Tanzania's economic growth. A one percent increase in public debt corresponds to a 2.4 percentage point increase in economic growth. The presence of a statistically significant Error-Correction Term suggests the correction of past deviations from long-run equilibrium, with 75% correction in the current period. These findings align with the Keynesian Theory, but they contradict the Adolph Wagner's hypothesis. The Johansen's co-integration test results support the existence of a long-run relationship between GDP and the public debt, and government expenditure. The paper therefore emphasizes efficient debt management and channeling borrowed funds into productive sectors in order to promote real economic growth and create opportunities, including employment. The paper also advocates for a correlation between increased borrowing and a rise in development expenditures, urging policymakers to align economic policies with macroeconomic objectives. These include promoting productive investments, employment opportunities, and sustainable economic growth. The strategic allocation of public debts to long-term projects in crucial sectors is seen as a meaningful contribution to stable economic growth, demanding effective management of public expenditures to ensure economic stability. Additional measures are proposed to control and maintain inflation levels, as well as strengthen the local currency through increased exports and domestic production.