This study investigates the relationship between good governance indicators and the Human Development Index (HDI) across countries worldwide over the period 1996 to 2021. using panel data, the analysis employs three econometric approaches: a fixed-effects linear panel  regression, Granger causality test, and apanel threshold regression (PTR) model to examine direct, reciprocal, and nonlinear effects of governance on human development. The linear model results indicate political stability, government effectiveness, and the overall governance index have positive and statistically significant effect on HDI, while the remaining governance indicators are not significant in this specification. Granger causality tests reveal  bidirectional relationships between HDI and most of the good governance indicators, with the exception of voice and accountability, suggesting a dynamic interaction between institutional quality and human development. furthermore, The PTR results provide strong evidence of nonlinear effects, showing that improvements in government effectiveness, rule of law, control of corruption, and regulatory quality exert significantly stronger impacts on human development in low-income compared to higher income countries .Overall, the findings underscore the critical role of institutional quality in fostering human development, particularly in poor countries, and highlight governance improvement as both a means and an objective of sustainable development.