This review covers a range of measures and methods frequently employed in the empirical analysis of global income inequality and global income distribution. Different determinant factors along with the quantification of their impacts and empirical results from different case studies are presented. A number of issues crucial to the study of global income inequality are also addressed. These are the concepts, measurement and decomposition of inequality, the world distribution of income and inequality measured at different levels of aggregation: global, international and intra-national. We analyze income at each of these levels, discuss the benefits and limitations of each approach and present empirical results found in the literature and compare them with those based on the World Income Inequality Database. Research on world income inequality supports increased awareness of the problem, its measurement and quantification, the identification of causal factors and policy measures that affect global income inequality.