Cambodian garment factories are involved in upstream processing for the global apparel value chain, and its industrial relations (IR) governance differs from the tripartite system, demonstrating the characteristics of multiple international actors participating in governance. Based on field work in Cambodia, including in-depth interviews with stakeholders in the garment industry, this study aims to answer two questions: How does IR governance in Cambodian garment industry reach internationalization? What "weapons " do the various actors use to fight, negotiate, and cooperate in IR governance in the Cambodian garment sector? Our data analysis reveals that in the governance of IR systems in the upstream garment industry of the global apparel value chain, international actors play a dominant role, which is different from the traditional "tripartite labor relations system." International actors include stakeholders from exporting and importing countries, international organizations, and lead firms. These actors utilize four "weapons ": political authority, economic leverage, public mobilization, and professional training to impact outcomes of the IR system in the sector.