Based on Blanchard and Perotti, Perotti, and Biau and Girard approaches, this paper evaluates the fiscal policy's effectiveness in Tunisia using Structural VAR model. The results show the short-run macroeconomic efficiency of a structural increase in public spending in Tunisia with a fiscal multiplier close to 1,806, in line with Keynesian's models. However, the estimated effect of a structural increase in tax revenues on activity is non-Keynesian. This is explained by the presence of a voracity effect in the case of the Tunisian economy.