Public debt is a key issue for government institutions, both because of the amount of its revenues, which partly compensate for the possible shortfall in tax collection, and because it is an essential instrument of fiscal policy for the government. This paper reviews the literature on the determinants of public debt in order to identify the explanatory variables of public debt according to the main theoretical and empirical studies. This work will support policy makers who have to obtain financial resources to cover essential and very necessary expenditures nowadays, such as health, education, or infrastructure investment, by controlling debt levels and fiscal pressure. The main policy implication we can derive from these results is that governments should use some of these instruments to reduce general government debt.