Global income inequality has been declining for several decades. We argue that global income inequality will reach its lowest level around 2027 and then will rise again. This development is the result of both economic and demographic forces. By combining economic projections with demographic developments and by using GDP per worker instead of GDP per capita in projecting income levels we emphasize the role of demographics in income inequality. Especially in the long run (after 2030), differences in population growth and population structure between countries in different stages of development are shown to increase global income inequality.