With the increase in awareness of environmental issues, companies and governments try to review their environmental policies. One of the most important policies for protecting the environment is the use of energy sources, which cause less or no harm to the environment. In this study, we examine the effect of institutional quality and the components of this institutional quality on green investments for G-20 countries. For this purpose, we employ static panel data analysis, as a main analysis, and dynamic panel data analysis as a robustness check. According to the main findings, institutional quality positively affects green investments and military spending reduces green investments. Also, robustness checks indicate that the effect of institutional quality and military expenditure of G20 countries on green investments is robust.