This book constitutes the refereed proceedings of the 6th International Workshop on Intelligent Virtual Agents, IVA 2006, held in Marina Del Rey, CA, USA, in August 2006.

The 24 revised full papers and 11 revised short papers presented together with 3 invited talks and the abstracts of 19 poster papers were carefully reviewed and selected from 73 submissions. The papers are organized in topical sections on social impact of IVAs, IVAs recognizing human behavior, human interpretation of IVA behavior, embodied conversational agents, characteristics of nonverbal behavior, behavior representation languages, generation of nonverbal behavior with speech, IVAs in serious games, cognition and emotion, and applications of IVAs.