In response to the growing interest in environmental peacebuilding (EP), the imperative of organizing and impartially assessing accumulated knowledge has intensified. Previous review articles on EP have predominantly used traditional narrative approaches, suggesting a lack of systematic selection in the studies they assessed. While some reviews have delved into intrastate EP, the more intricate realm of interstate EP, which encompasses complex social and political mechanisms, has been largely overlooked. Addressing this gap, a systematic literature review of interstate EP was conducted, with the primary aim of characterizing and categorizing two decades of empirical studies. The Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) approach facilitated the analysis of 417 EP articles which were reduced to 32 through manual screening. As for general trends, despite a yearly increase in publications, a persistent scarcity of empirical research in interstate EP remains. While positive trends, including a rising number of authors from assessed countries, have emerged, gender imbalances persist. Regarding the interplay between natural resource management (NRM) and peacebuilding, 75% of the studies found that NRM plays a role in reducing conflict and fostering peace. On the other hand, many studies did not offer clear suggestions to enhance the theoretical framework, pointing to a need for further theoretical development.