Based on the previous studies, the hypothesis of this research is that the higher the level of gender equality in a state, the higher level of its peacefulness. It is a quantitative study using linear regression analysis with three variables, namely Global Peace Index (GPI) as a dependent variable, Gender Inequality Index (GII) as an independent variable and Human Development Index (HDI) as a control variable. The data of 139 states from year 2013 were submitted into Statistical Package for Social Sciences (SPSS) software. The result shows a significant and positive linear relationship between gender inequality and a high level of conflict, which confirms the hypothesis. However, HDI shows to be less reliable as a control variable due to issues with multicollinearity (heavily related independent variables). Further studies should replace the HDI with another control variable.