This research seeks to evaluate the impact of drug policy reform in Mexico within the larger Latin American context. Through theoretical and statistical analyses, I use the case study of the municipal Police Department in Tijuana to understand the implementation of Mexico’s 2009 “narcomenudeo” drug policy reform that decriminalized drug possession for personal consumption. Using internal unpublished police data, I demonstrate that the policy shift did not appear to impact the policing of drug arrests over the five years following the implementation of the reform. Police education efforts designed to improve officer understanding of the reform and its street- level implementation found low baseline knowledge of the decriminalization policy, shedding light into the mechanisms impeding its application. Training evaluation suggested that officers increased their legal knowledge, but that training uptake was shaped by level of educational attainment. Ultimately, these findings add to the emerging implementation science literature on the importance of structural interventions to better align public health-oriented drug policy reforms with their intended impact in Latin America and elsewhere.