Over the course of the 20th Century, several international wildlife treaties were created to address the problem of species’ overexploitation. Despite these efforts, extinction threats and concomitant biodiversity losses have escalated and now also increasingly threaten the wellness of human communities. This warrants an examination of the ability of treaty rules to protect individual species and biodiversity; not only in the realm of anarchy (i.e., the international governance sphere), but also within the hierarchical domestic legislative structures of Contracting Party states. However, comparative analyses on the feedback between international wildlife treaties, national conservation laws, and local species conservation outcomes remain a neglected scholarly pursuit. I draw on the Institutional Grammar Tool to examine the horizontal (within and across treaty regimes) and vertical (across governance levels) feedbacks of four international wildlife treaties and their domestic counterparts in two countries. By parsing the treaty texts, relevant resolutions, and domestic legislation into their constituent institutional statements (e.g., norms, strategies, or rules) and rule types (e.g. position rule, payoff rule), I provide a comparison of institutional diversity across treaty regimes and an assessment of the fit between the rules at the international and the national governance level. Preliminary findings suggest a trade-off between adaptable international treaty rule structures and necessary national implementation standards, as well as the need for rules that facilitate collective action and information flows across treaties and governance levels.