This article examines the successful legal battle led by Mayan beekeepers participating within an activist network against the permission granted to Monsanto in 2012 by the Mexican government to commercialize genetically modified soybeans in the Yucatán Peninsula. Our approach emphasizes the relevant role of rights-advocacy lawyers and their organizations working together with local grassroots, Mayan beekeepers and scholars in a legal battle that puts forward the rights to a healthy environment and to indigenous self-determination. We consider the judiciary’s response to such demands and, in doing so, we explain why some collective rights, such as the right to free, prior, and informed consultation, were more appealing to Mexican judges while others were blatantly ignored. Likewise, we explore why and how a legal fight against Monsanto GM soybean became a struggle for the recognition of Mayan communities’ self-determination expressed in the right to free consent and self-consultation. Our research sheds light on some positive and unexpected outcomes of legal mobilization against GMOs in the Yucatán Peninsula, while acknowledging that GM soybean, despite being banned, is still produced and marketed illegally in the country.