The rise of multi-stakeholder institutions (MIs) involving the ultra-processed food (UPF) industry has raised concerns among food and public health scholars, especially with regards to enhancing the legitimacy and influence of transnational food corporations in global food governance (GFG) spaces. However, few studies have investigated the governance composition and characteristics of MIs involving the UPF industry, nor considered the implications for organizing global responses to UPFs and other major food systems challenges. We address this gap by conducting a network analysis to map global MIs involving the UPF industry, drawing data from web sources, company reports, business and market research databases, and academic and grey literature. We identified 45 such global food system MIs. Of these, executives from the UPF industry or affiliated interest groups held almost half (n = 263, or 43.8%) of the total 601 board seat positions. Executives from a small number of corporations, especially Unilever (n = 20), Nestlé (n = 17), PepsiCo Inc (n = 14), and The Coca-Cola Company (n = 13) held the most board seat positions, indicating centrality to the network. Board seats of these MIs are dominated by executives from transnational corporations (n = 431, or 71.7%), high-income countries (n = 495, or 82.4%), and four countries (United States, Switzerland, United Kingdom, and the Netherlands) (n = 350, or 58.2%) in particular. This study shows that MIs involving the UPF industry privilege the interests of corporations located near exclusively in the Global North, draw legitimacy through affiliations with multi-lateral agencies, civil society groups and research institutions, and represent diverse corporate interests involved in UPF supply chains. Corporate-anchored multi-stakeholderism, as a form of GFG governance, raises challenges for achieving food systems transformation, including the control and reduction of UPFs in human diets.