The dire need to expand the frontiers of the enforcement mechanism of the rules of international humanitarian law through the international institutions has been of a global concern for ages. Driven primarily by efforts to enforced and promote the rules of international humanitarian law, there is a need to develop measures capable of promoting the rules of international humanitarian law through the international institutions. The objective of this paper is to analyze and establish that expanding the frontiers of the enforcement mechanism of the rules of international humanitarian law through the international institutions bothering on individual or state responsibility will further strengthen the low level of enforcement of these rules. However, this paper noted that there is a significant enforcement gap both at the regional and international levels. Further, this paper argues that in order to guarantee a high level of enforcement of these rules both at the regional and universal levels, a more integral approach on the role of international institutions is capable of addressing the enforcement gap of the rules of international humanitarian law. This paper adopts a diagnostic approach based on a review of literatures, which is achieved by synthesis of ideas. This paper concludes with recommendations among others that in order to boast the purpose for which the rules of international humanitarian law were made, the level of enforcement of these rules should be expanded to fill the enforcement gaps at the domestic, regional and universal levels.