In this article, we investigate the causality links between behavioral factors and the decision to adopt IFRS in developing countries until the year 2013. We implement this empirical model by using the neo-institutional approach and based on a sample of 108 developing countries. Our empirical results show that there exists bidirectional causal relationship between the majority of the developed behavioral variables and the decision of adopting or not IFRS by developing countries. They also indicate through multivariate analysis that the selection of IAS / IFRS by developing countries is primarily legitimized by institutional and social pressures (institutional isomorphism). These empirical insights are of particular interest to local accounting standard setters of selected countries since they can provide a better discernment of factors that can encourage the adoption of IAS IFRS.