Purpose: The purpose of the paper is to study the problem of socio-economic inequality from the positions of the neo-institutional economic theory, to determine the causal connections of emergence and manifestation of this problem as a barrier on the path of sustainable development and to develop institutional measures for its solution based on state regulation. Design/methodology/approach: The scientific and methodological basis of this research is based on regression analysis, which is used for creating and analyzing the regression curves. For the fullest coverage of countries of the world and provision of high representation of the research results, the objects of the research are countries from each category that were distinguished according to their position in the global rating of countries as to the index of sustainable development, calculated and compiled by Sustainable Development Solutions Network (2019). Findings: It is substantiated that financial inequality is a result of violation of the principles of social justice—primarily, in the labor market. The institutional approach, which is used for studying the problem of socio-economic inequality, allows presenting this problem as a result of the action of social institutes with own system of rules and norms and offering the institutional measures of regulation, which are to influence the rules and norms in society in the labor market. Due to this, the object of regulation is not the consequence but the reasons—and better and long-term results are achieved. Originality/value: It is proved that social justice is the key condition of overcoming socio-economic inequality, formation of inclusive society and achievement of balance of the global economic system—thus opening a path to sustainable development. Four “institutional traps” are determined, which establish the practices of violation of the principles of social justice in the system of norms and rules of behavior of the labor market's participants. The authors determine perspectives and directions and offer measures of state regulation of the institutes of socio-economic inequality for its overcoming and provision of sustainable development of national economy and the global economy. © 2020, Emerald Publishing Limited.