This research aims to analyze the effect of government spending on health, education, and infrastructure on affecting the human development index (HDI) in Simalungun Regency partially and simultaneously. This research uses multiple linear regression analysis models. Sources of data used in the form of secondary data obtained from the publication data of the Central Statistics Indonesia (BPS) and data Regional Development Planning Agency (BAPPEDA) Simalungun Regency with the period 2003-2020. Partially, the variables of government spending in the health, education, and infrastructure sectors have a positive and no significant effect on the human development index in Simalungun Regency. Meanwhile, simultaneously, government spending variables in the health, education, and health sectors have a significant effect on HDI in Simalungun Regency. And then Government spending in the infrastructure sector has the most dominant effect on HDI in Simalungun Regency compared in health and education. The coefficient of determination (R2) explains the variables of the health sector, the education sector, and the infrastructure sector can explain the variation of the HDI variable by 0.750 or 75.0%. While the rest is explained by other variables do not study in this investigation.