This three-volume set constitutes the refereed proceedings of the First World Conference on Explainable Artificial Intelligence, x AI 2023, held in Lisbon, Portugal, in July 2023. The 94 papers presented were thoroughly reviewed and selected from the 220 qualified submissions. They are organized in the following topical sections: ?Part I: Interdisciplinary perspectives, approaches and strategies for x AI; Model-agnostic explanations, methods and techniques for x AI, Causality and Explainable AI; Explainable AI in Finance, cybersecurity, health-care and biomedicine.Part II: Surveys, benchmarks, visual representations and applications for x AI; x AI for decision-making and human-AI collaboration, for Machine Learning on Graphs with Ontologies and Graph Neural Networks; Actionable e Xplainable AI, Semantics and explainability, and Explanations for Advice-Giving Systems.Part III: x AI for time series and Natural Language Processing; Human-centered explanations and x AI for Trustworthy and Responsible AI; Explainable and Interpretable AI with Argumentation, Representational Learning and concept extraction for x AI.