This book constitutes the refereed proceedings of the 5th International Workshop on Intelligent Virtual Agents, IVA 2005, held in Kos Island, Greece in September 2005.

The 26 revised full papers and 14 revised short papers presented together with the abstracts of 15 poster papers were carefully reviewed and selected from 69 submissions. The papers are organized in topical sections on IVAs and education, conversational agents/NLP, IVA architectures, cognition, reasoning and behaviour, nonverbal communication, storytelling/interactive narrative, social intelligence, emotions/affect/personality, evaluation and methodology, and the poster session.