ARGONAUTE (AGO) proteins are the final effectors of small RNA-mediated transcriptional and post-transcriptional silencing pathways. Plant AGO proteins are essential preserving genome integrity, regulating developmental processes, and during stress responses and pathogen defence. Since the discovery of the first eukaryotic AGO in Arabidopsis thaliana, our understanding of these proteins has grown exponentially throughout all eukaryotes. However, many aspects of AGO proteins modes of action and how these are influenced by their subcellular localizations have remained to be elucidated. Here, we provide an updated and comprehensive view of the evolution, domain architecture/roles, expression pattern, subcellular localization, and biological functions of the ten AGO proteins in Arabidopsis.