This book constitutes the refereed proceedings of the 5th International Conference on Web Engineering, ICWE 2005, held in Sydney, Australia in July 2005.

The 33 revised full papers, 36 revised short papers, and 17 poster and demo papers presented together with abstracts of 4 invited keynotes were carefully reviewed and selected from 180 submissions. The papers are organized in topical sections on Web engineering milieu, evaluation and verification, non-functional requirements and testing, query and retrieval, applications, ontologies and XML, semantics and semantic Web, Web security, Web services and application design, and miscellaneous.