This volume constitutes the proceedings of the 5th International Workshop on Trends in Enterprise Architecture Research (TEAR), held in Delft, The Netherlands, on November 12, 2010. The main objective of the workshop is to identify major trends and challenges in enterprise architecture research by providing a discussion forum where researchers and practitioners can exchange experiences, problems, and ideas.The 7 papers presented were extensively reviewed and selected from 15 submissions. They report on core concepts and the effectiveness of enterprise architecture, on architecture description languages, and on exemplary case studies.