ABSTRACT This study focuses on the sustainability of public finances in relation to economic growth in Morocco for the period from 1987 to 2019. We set out to explore therewith the non-linear relationship between government size, the level of fiscal discipline and economic growth. This issue at hand has attracted broad public interest and decision-makers’ attention in Morocco, especially after the financial crisis of 2008 and during the COVID-19 pandemic. In order to determine government optimal size, we apply the Hansen's approach which postulates the coexistence of different fiscal regimes conditioned by the public debt, government expenditures, and tax revenues in the form of a non-linear inverted-U curve. These regimes are separated by an optimal threshold maximizing economic growth below which the impact is positive and above which the impact becomes negative, as the rising side of the curve is interpreted as consequence of higher taxes providing more resources for public investment, which in turn promotes growth. Once the economy reaches the slippery side of the curve, more taxes and excessive public debt become more distortionary and negatively correlated with economic growth. Our findings indicate that Morocco is relatively in a prudential fiscal stance with recessive effects on growth.