The objective of this work is to examine the effect of public debt levels on economic growth in ECOWAS states over the period 2000 to 2019. Using a PSTR model, the results show that public debt has significant non-linear effects on economic growth. The estimates reveal the existence of a debt threshold estimated at 42.59% of GDP, below which additional debt has a positive effect on growth. On the other hand, above 42.59% of GDP, public debt has a negative effect on growth.The results of this study give rise to a number of economic policy recommendations.