The 18th International Conference on Engineering Design, ICED11, was held August 15-18th 2011 at The Technical University of Denmark (DTU), Copenhagen. The Conference is the flagship event of the Design Society, a society dedicated to contributing to a broad and established understanding of development and design. The ICED series of conferences has a long tradition, which started in 1981 with the first ICED in Rome.A total of 419 papers were presented at ICED11, each double-blind reviewed by multiple reviewers. The papers included research papers and case studies on a variety of topics concerned with design thinking, theory, and practice, with a premium placed on evidence-based research. The papers are published in a total of ten volumes of Proceedings, in addition to electronic publication. This volume contains 49 papers concerned with Human Behaviour in Design: issues such as human experience, cognition, emotion, empathy and uncertainty in the context of design.