Similar to many other countries, Mexican schools have historically been recognised as important sites for health maintenance and promotion. The nature of targeted health promotion interventions in Mexican schools has been influenced by specific national socio-historical conditions. Currently, these health interventions are primarily targeting obesity, which for a variety of complex economic, political and social reasons, is considered to be a serious health problem for the country. As a result, school-based obesity policies (SBOP) limiting the availability of junk food and sugar-sweetened beverages, promoting health literacy, and encouraging children to do more physical activity have been created and implemented in a variety of ways in the school context. Taking as a starting point an understanding policy as a complex process shaped by cultural, political and economic conditions, the broad purpose of my research is to understand how and under what conditions SBOPs have been developed and enacted in Mexico. The specific focus of this paper is on the interests, struggles and power relations involved in the policy process. The data have been generated through document analysis of three policies in Mexico; multiple interviews with civil society organizations’ members, education and health authorities at national and state level, and academics; and additional interviews with teachers, school leaders and parents, as well as observations in two primary schools in one Mexican state. SBOPs in Mexico have been developed and enacted by multiple stakeholders including the Mexican government, the private sector and the civil society sector. Preliminary findings suggest that the private section and specifically the Beverage and Food Industry (BFI) is an incredibly powerful player in the development of SBOPs in Mexico. Given the economic power and seemingly unlimited resources at the disposal of the BFI, it is perhaps unsurprising, that they have gained a significant foothold in policymaking and policy enactment regarding obesity prevention and the health work at schools. Similar to what research has reported in other countries, both the government and the BFI prefer SBOPs to other policies (for example the soda taxation policy) because SBOPs are not perceived as having any significant economic implications for the BFI or the country. The absence of any funding allocation by the government for the implementation of SBOPs means that if schools do wish to enact various policy recommendations, they are often reliant on the private sector to make this happen.