<p>Mutualistic interactions between plants bearing extrafloral nectaries (EFNs) and ants are key ecological processes in many ecosystems, particularly in the Neotropics. These interactions, where plants offer nectar to attract ants in exchange for protection against herbivores, are influenced by various biotic and abiotic factors. This review synthesizes current knowledge on the role of EFNs in plant defense, focusing on their impact on ant communities, plant–herbivore dynamics, and the facilitation of interplant interactions. I explore how abiotic conditions, such as temperature, precipitation, and seasonal changes, affect EFN production, ant abundance, and herbivore pressure. The review also discusses how the composition of ant communities and environmental factors shape the effectiveness of these mutualisms, with a particular emphasis on the role of dominant ants and their aggressive behaviors. Additionally, I address how plant phenology, such as leaf flushing and flowering, interacts with ant activity and herbivore abundance, influencing the temporal dynamics of plant protection. The facilitation between plants, mediated by the shared presence of ant species, further enhances the understanding of plant community dynamics in the context of mutualistic networks. Finally, I discuss the potential effects of climate change on these interactions, highlighting how shifts in environmental conditions could impact plant–ant–herbivore relationships and the coevolution of these species. This review underscores the importance of understanding the complex interplay between plants, ants, and environmental factors to predict the ecological outcomes of mutualistic interactions in a changing climate.</p>