Abstract : The general topic of this work is the stabilizing influence of appropriate fiscal policies on the economy's dynamics. In this thesis, stabilization policies are understood as a means to lower or rule out the likelihood of endogenous fluctuations in the economy. The first chapter examines, in a real economy, the stabilizing properties of linearly progressive income taxes, resembling the tax codes with brackets that prevail in many developed countries. The second chapter highlights the fact that the stabilizing (counter-cyclical) influence of income tax progressivity is weakened with the introduction of a realistic fiscal scheme allowing firms to deduct maintenance and repair expenditures when calculating pre-tax profits. The third chapter studies the impact of income taxation in a monetary economy with heterogeneous agents. The analysis confirms the idea that fiscal progressivity lowers the probability of endogenous fluctuations in the economy. However, in such a monetary frame, in contrast with the real economies pictured in the first two chapters, it is shown that even high levels of tax progressivity can not completely rule out the occurrence of endogenous fluctuations. Eventually, the last chapter investigates how fiscal policy can affect aggregate volatility and growth in credit constrained economies. In an endogenous growth model combining capital market frictions with unequal access to investment opportunities across individuals, it is shown that an appropriate fiscal policy, even linear, consisting of taxing labor income and organizing transfers towards innovating investment, is able to remedy the shortage of funding for these investments during slumps, stabilize the economy's dynamics and place it on a sustained permanent growth path.