PurposeThe purpose of this paper is to examine the effect of state fragility on select indicators of human development and identify aspects of state fragility that have the greatest impact on poverty reduction and sustainable development. The paper also explores the impact of social cohesion on human development as well as the mediating role of state legitimacy in mediating the relationship between social cohesion and human development.Design/methodology/approachThe study is based on data from 180 countries and uses ordinary least squares regression and mediation analysis to explore the effects of social cohesion on human development.FindingsThe findings show a significant relationship between state fragility and human development. It suggests that policies and efforts aimed at enhancing social cohesion would have the most significant impact on human development. The findings also show that social cohesion not only has a direct effect on human development but it also has an indirect effect on human development through state legitimacy (mediator).Practical implicationsEven though state fragility has been largely associated with low income countries, different facets of fragility are manifested in various countries regardless of levels of economic development.Originality/valueThe study is timely in view of the evidence of increasing state fragility in many countries. Furthermore, this is the first scholarly work linking lack of social cohesion, state fragility and human development.