Income inequality is one of the most significant impediments to the development and welfare of countries. Increased income inequality can cause to social conflict and affects social coherence negatively. Such economies become unstable and unsustainable in the long run. An inequitable distribution of income adversely affects the economic development in developing countries and inhibits the emergence of economic and political institutions that could support growth and investment. Events, which have a profound effect on societies, such as wars, revolutions, technological development and great economic crisis, might result with the elimination of income inequality in a region or country in a relatively short time. However, without such profound events, the tradition of income inequality could take centuries of efforts to achieve certain change. The present study, therefore, discusses the history of income inequality in the world, the current situation and future forecasts and presents relevant findings and suggestions.