Trans fatty acids (TFA) are a major risk factor for cardiovascular disease (CVD), and are consumed in large quantities in low- and middle-income countries as they are used to produce low cost, commonly eaten processed food products. International organizations agree that evidence linking TFA and CVD is strong enough to warrant public health action. This study investigates barriers and opportunities that exist for TFA policy development in low- and middle-income countries, through a literature review of international TFA policy and stakeholder analysis. Previous national policy responses have mostly been in developed countries. Voluntary reduction of TFA by the food industry, following food labelling and/or consumer lobbying, has been the approach in several countries but with varying levels of success, and resulting in major differences in formulation of products between countries. Canada and New York have now moved from voluntary to mandatory approaches. Only three countries have regulated the TFA content of food. Common factors for successful TFA reduction include increased consumer and political awareness of the health impacts of TFA and the need for champion consumer organizations. A stakeholder analysis, using the Mexican policy context as a case study, explored contextual issues influencing implementation of TFA regulation in low- or middle-income countries. Although the public health context seemed to be appropriate to promote TFA policy, the issue is not on the political agenda because it lacks legitimacy and support as a health or regulatory issue. The food industry and government resist the need for regulation, and there is no organized health or consumer lobby to counter this. This is likely to be the case in other middle- and low-income countries.