In comparison to other high-risk industrial sectors, human rights due diligence (HRDD) in the arms sector remains unclear and underdeveloped. This article elucidates how supply chain regulations can provide pertinent guidance for clarifying and elaborating the standards and requirements of the HRDD obligations of arms companies. Part I reaffirms the importance of independent HRDD obligations for arms companies due to the significant human rights risks posed by arms exports. Part II contextualises the limitations in the development of HRDD in the arms industry by examining the corporate policies of major arms companies. Part III explicates why supply chain regulations for conflict minerals are suitable guidance for clarifying and elaborating the HRDD obligations of arms companies. Part IV details five elements of an HRDD framework for arms companies that are essential for comprehensively identifying, evaluating and addressing the human rights risks of arms exports. Part V offers concluding remarks.