Welcome to the proceedings of the 18th International Conference on Intelligent Virtual Agents (IVA). IVA is the annual interdisciplinary conference in which leading scientists from around the world present and discuss their latest work on intelligent virtual agents. These agents are inter-active characters which humans can interact with. They often have anthropomorphic elements to evoke responses that humans would exhibit when interacting with other humans. For this, agents use natural human communication modalities such as facial expressions, speech, and gesture. Besides these interaction modalities, the agents are capable of real-time perception, artificial cognition, and actions in the social environment they operate in. Constructing and studying these IVAs requires knowledge, theories, methods, and tools from a wide range of fields such as computer science, psychology, cognitive sciences, communication, linguistics, interactive media, human-computer interaction, and artificial intelligence. All these disciplines are represented in these proceedings. This volume contains the papers presented at IVA 2018: Intelligent Virtual Agents held on November 5-8, 2018 in Sydney. There were 75 submissions. Each submission was reviewed by at least 3, and on the average 3.3, program committee members. The committee decided to accept 17 full papers, 31 short papers and 18 extended abstracts.