Background: Breastfeeding is important for the health and development of the child, and for maternal health, in all country contexts. However, global sales of breast-milk substitutes (BMS), including infant, follow-up and toddler formulas, have ‘boomed’ in recent decades. This raises the importance of international food standards established by the Codex Alimentarius Commission (Codex) on the safety, composition and labelling of BMS. Such standards appear to be strongly contested by governments, industry and civil society groups, yet few studies have investigated the politics of Codex standard-setting processes. The aim of this paper is to understand who participates in decision-making, and how actors frame and contest proposals to revise the Codex Standard on Follow-up Formula (FUF). Methods: We adopted a case study design involving two steps. First, we enumerated government, industry, civil society, and international organization stakeholders participating in standard-setting processes of the Codex Committee on Nutrition and Foods for Special Dietary Uses (CCNFSDU). Second, we conducted a framing analysis of stakeholder inputs during the FUF standard revision in CCNFSDU meetings. Publicly available online meeting reports (2015-2019) were retrieved, analyzed using a theoretical framework, and organized thematically. Results: High-income country (HIC) delegates greatly outnumbered those from other country income categories. Industry representation was higher compared with other observer categories Member state delegations included more industry representation than civil society representation, and were occasionally the only member state delegates. Industry stakeholders framed arguments in terms of trade implications, science, and flexible standards. Civil society groups used public health, science, and pro-breastfeeding frames. Conclusion: Codex BMS standard-setting procedures are dominated by HICs and industry groups. Limited representation of civil society, and of middle- and low-income countries, suggest actions are needed to substantially increase support for their involvement at Codex. Such representation may help to counteract power asymmetries and commercial influences on food standards for infants and young children.