Recent research suggests that there is an urgent need to create transitions to agroecology to address the many ecological, social, and ethical problems caused by the hegemonic Corporate Food Regime. In the Global South, however, there are already numerous and diverse agroecological initiatives driven by peasant communities, indigenous peoples, and grassroots organizations. Although many agroecological innovations developed by such grassroots groups have been identified, they have seldom been analyzed under a specific theoretical framework of innovation (e.g., grassroots innovation). To contribute to this gap, this paper reviews the existing literature on agroecology that is concerned with innovation. Further, it analyzes three case studies in Michoacán (Mexico) using two theoretical frameworks: grassroots innovation and transitions to sustainability. The cases illustrate different visions and ways of practicing agroecology, as well as the development of several agroecological innovations. The study provides empirical evidence about the potential of grassroots groups in the Global South for creating innovations that can be useful in the transition to a more just and sustainable food regime based on agroecology. This evidence has important implications for policymaking in agriculture, climate change, and biocultural conservation.