This book constitutes the refereed proceedings of the Third European Conference on Smart Sensing and Context, EuroSSC 2008, held in Zurich, Switzerland, October 29-31, 2008.The 17 revised full papers presented together with one invited paper were carefully reviewed and selected from 70 submissions. The papers are organized in topical sections on smart objects, spatial and human context inference, context processing and quality of context, as well as context-aware interaction and case studies.