The inappropriate use of antibiotics poses a risk to individual health, is a waste of health resources, and triggers antibiotic resistance, a global health problem. Despite strategies promoted internationally to address antibiotic misuse and resistance (AMR), few low and middle-income countries have fully incorporated them into their national health policies. There is scarce research on the factors that affect the development of AMR policies at the national level. The present study addresses this gap by applying a policy-analysis approach to understand agenda setting, policy inaction and policy change with regard to AMR, focusing on the case of Mexico. This study is designed as a longitudinal case-study, looking at events between 2001 and 2012 in Mexico, which cover two periods of government. The study used Kingdon’s multiple streams (MS) theory of agenda-setting to guide the analysis, explaining both when the issue of AMR was denied a position on the agenda (first period studied) and when the issue gained agenda status and a policy change occurred (second period studied). The methods used were semi-structured interviews with key social actors, document analysis and media analysis. The following factors hindered AMR inclusion in the health policy agenda during the 2000-2006 administration: a) low problem visibility and a narrow definition that pulled AMR away from the scope of public policies; b) lack of clarity on the policy alternatives and their feasibility; c) absence of policy entrepreneurs promoting these policies; d) within the health-reform context, improving medicine stocks was the priority. During the 2006-2012 administration, the problem of self-medication with antibiotics gained visibility when it was related to the 2009 influenza pandemic; a group of specialists acted as policy entrepreneurs supporting AMR policies. The national health crisis and a previous designation of an institutional body to control medicine sales favoured agenda placement and the development of a narrow-focused regulation, but hindered the formation of a comprehensive national policy on AMR. The usefulness of Kingdon’s theory in examining AMR agenda-setting, in the context of Mexico, is explained. The research findings are discussed in light of other studies to draw lessons for Mexico and other countries aiming to develop AMR policies.