The popularity of the International Court of Justice (ICJ) is discussed controversially. This paper examines the usage of the ICJ by both all UN member states and the top-ten economies of the world. In addition, five hypotheses explaining the decrease in the ICJ’s usage by the major powers of the world are presented as follows: (I) the home-bias of judges, (II) the diversification of international tribunals, (III) changes in the composition of the cases filed, (IV) the (re-) allocation of power, and (V) an increased heterogeneity of external institutions among UN member states. We find empirical evidence that the increase in UN membership has led to increased heterogeneity, which again has led to a decline in usage of the ICJ by the top-ten economies.