In theory, the effects of debt on economic growth were particularly debated in the post-war period following the sharp increase in the public debt of advanced countries, showing particularly two visions: the Keynesian short run vision and the classic long run vision. In the short run, public spending stimulates aggregate demand in the context of Keynesian prices and wage rigidities. However, in the long run, the economy adheres to the classic view stating that public debt reduces the capital stock and productivity, leading to production decrease. The relationship between public debt and economic growth has been recently revived following the 2008 economic crisis which leads to the sovereign debt issues in advanced countries.In the long term, economic theories seem to be at least unanimous on the negative effects of public debt on economic growth. This finding has become so ingrained in everyone's mind that it seems to legitimize claims about a possible existence of a public debt threshold that reduces long-term economic growth. Particularly, Reinhart and Rogoff (2010) have argued on the existence of a debt to GDP threshold of 90% beyond which economic growth would be impaired. As a consequence of such result, which has a strong implication in terms of economic policies, a continuous influx of work examining the question of debt threshold has emerged. In the short term, the analysis is more focused on the composition of public spending and the size of its multipliers.This thesis aims to analyze, for a sample of 20 developed countries, the relevance of the arguments in favor or against a universal above-mentioned threshold, which economic theory does not seem to indicate formally. We show in Chapter 1 that the existence of such threshold, especially common to all countries, seems to create empirically a cleavage rather than a consensus. This finding was more argued by an application based on recent techniques of econometric analysis (Hansen, 2017) searching endogenously for a turning point in the public debt and economic growth relationship.In addition, Chapter 2 is particularly devoted to assessing the short-term effects of public debt on economic growth, particularly through the evaluation of the effects of public debt on expenditure multipliers. The importance of this exercise is emphasized as a part of the revived debate on fiscal multipliers, which was triggered by Auerbach and Gorodnichenko (2012). Multipliers revealed to be sensitive to several determinants, including the public debt (budget deficit) and the business cycle. We adopted an SVAR methodology to assess spending multipliers as passthrough of public debt effects to economic growth.Chapter 3 is devoted to assessing the long-term effects on economic growth in an endogenous growth model. Hence, a parameterized formula has been simulated for a potential debt that a country could target to finance its productive investments without overcoming it. This potential debt ratio, linked to economic growth and the productivity of public capital as well as the interest rate, is dynamic, specific to each country and evolves over time.In the three chapters, the thesis opposes any common debt threshold that applies to all countries. The subject of economic growth and public debt remains one of the most debated topics in macroeconomics since the 2008-2009 financial crisis.