Intelligent Virtual Agents (IVAs) are embodied digital characters situated in a virtual, augmented, or mixed reality environment that look, communicate, and act like ‘living’ creatures, real, or fictional. A distinctive characteristic of IVAs is that their behavior should exhibit some aspects of human intelligence, including autonomous behavior, communication and coordination with other IVAs, dialogues with humans, and learning capabilities. Additionally, IVAs are expected to be believable, i.e., to have a consistent behavior, to exhibit some form of personality and emotions, to communicate and interact in a plausible way, etc. There are plenty of application areas that may benefit from IVAs, including intelligent non-player characters (NPCs) in computer games, virtual tutors in educational software, virtual assistants, ‘living’ characters or virtual guides in digital heritage environments, animated crowd in simulations, etc.

The design and development of effective IVAs requires the adoption of theories, models and tools from related disciplines, including Artificial Intelligence, Artificial Life, Virtual Reality and Human–Computer Interaction, and, as such, it presents significant research challenges. Generic issues, such as design and evaluation methodologies, development tools and platforms, and believability assessment, as well as more specific issues related to agent behavior, interaction and communication, are under active research. Furthermore, the recent emergence of novel interaction techniques and devices, including mobile augmented reality, natural user interfaces and low-cost immersive VR, presents further challenges for IVA embodiment and communication with humans.

For this Special Issue, authors are encouraged to submit original research articles, case studies or reviews on IVAs and their applications. Of particular interest are articles that explore important theoretical or applied aspects related to the design and evaluation of believable IVAs, their integration with emerging interaction technologies, and/or their effective usage in application fields, such as education, entertainment, and cultural heritage.