This paper defines the relationship between inequality and economic development, analyzes the impact of economic growth on income inequality and poverty rate. The study uses different indicators and panel data over 10 years and across 46 countries worldwide. As the Kuznets Curve suggested, a country’s inequality level and economic development share a non-linear relationship. The author applies this concept to 3 different models and found different results between low and middle-income countries and high-income countries. In result, this study confirms the Kuznets law as the author finds an unequal income distribution in low and middle-income countries.