Argumentation is the study of the processes and activities involving the production and exchange of arguments, where arguments are attempts to persuade someone or something by giving reasons for accepting a particular conclusion as evident. As such, argumentation provides procedures for making and explaining decisions and is able to capture diverse kinds of reasoning and dialogue activities in a formal but still intuitive way, enabling the integration of different specific techniques and the development of trustable applications. For these reasons, over the last two decades formal argumentation has become a main research topic in AI. A variety of theoretical models at different levels of abstraction have been extensively studied, ranging from purely abstract models to concrete implemented systems, argumentation solvers have been developed to identify the justification status for arguments according to different semantics, and a variety of applications of argumentation have been proposed for several fields, ranging from modeling dialogues in social networks to law and medicine.
Given that the study of argumentation is inherently interdisciplinary, the goal of the workshop, co-located with the International Conference of the Italian Association for Artificial Intelligence (AIxIA 2021), is to stimulate discussions and promote scientific collaboration among researchers not only directly involved in argumentation, but also from research fields indirectly related to argumentation. In this respect, at least two directions can be envisaged:

• Cross-fertilization with different fields (including non-monotonic reasoning, logic programming, linguistics, natural language processing, philosophy and psychology, just to mention a few of them) is needed to update and extend foundations in Argumentation Theory, as well as tackling a number of open issues that are currently debated in the area.
• Inter-disciplinary collaborations are necessary to foster the adoption of argumentation as a viable AI paradigm with a wide range of applications.
  In Italy, several research groups from different universities and institutions have been involved in argumentation in recent years. One of the aims of the workshop is also to bring together researchers working in argumentation to foster collaboration and the development of a specific national research community.