External Debts and economic growth in Nigeria is analysed using the threshold auto regressive model to properly estimate the level of debt sustainability in Nigeria. The text exposes students and researchers in Economics and other related disciplines to external debts as its relates to developing countries and Nigeria in particular. In order to achieve the aim diagnostic tests were conducted using Augmented Dickey Fuller Unit Root Test, Co-integration, and Error Correction Model. Threshold Autoregressive model was used to test the level of debt sustainability in Nigeria within the period under review.