Unhealthy diets are increasing contributors to poor health and mortality in low- and middle-income countries (LMICs). Government interventions targeting the structural drivers of unhealthy diets are needed to prevent these illnesses, including nutrition labelling regulations that create healthier food environments. Yet, implementation remains slow and uneven. One explanation for slow implementation highlights the role of politics, including powerful ideological discourse and its strategic deployment by economically powerful actors. In this article, we advance research on the politics of nutrition policies by analysing political discourse on nutrition labelling regulations within an influential and under-studied global institution: the World Trade Organization (WTO). We identified WTO Technical Barriers to Trade (TBT) Committee meeting minutes with reference to nutrition labelling policies proposed by Thailand, Chile, Indonesia, Peru, Ecuador, Bolivia, and Uruguay (2007–2019; n = 47). We analysed the frames, narratives, and normative claims that feature in inter-country discourse within TBT meetings and examined how actors mobilize ideological and material sources of power via these statements. We find that informal government challenges to nutrition labelling proposals within the Committee featured a narrative that individualized the causes of and solutions to poor diet, downplayed harms from industrialised food products, and framed state regulation as harmful and unjust. These non-technical claims mobilised neoliberal ideology and rhetoric to contest the normative legitimacy of members’ proposals and to de-socialize and de-politicize poor diets. Furthermore, high-income countries (HICs) re-framed policy goals to focus on individual determinants of poor nutrition whilst calling for their preferred policies to be adopted. Patterns of discourse within TBT meetings also had striking similarities with arguments raised by multi-national food corporations elsewhere. Our findings suggest that non-technical and ideological arguments raised during TBT meetings serve as inconspicuous tools through which nutrition labelling policies in LMICs are undermined by HICs, industry, and the powerful ideology of neoliberalism. •Critical discourse analysis of informal challenges to nutrition labelling polices.•Informal challenges occurred at the World Trade Organization (WTO), 2007–2019.•Challenges individualized, de-socialized, and de-politicized unhealthy diets.•Challenges invoked neoliberal ideology and industry rhetoric.•Discourse, and its deployment by powerful actors, may inconspicuously shape policy.