This volume constitutes the proceedings of the 16th International Conference on Web Services, ICWS 2018, held as Part of SCF 2018 in Seattle, WA, USA in June 2018. The 31 full papers together with 1 short paper published in this volume were carefully reviewed and selected from 116 submissions. They are organized in topical sections such as Web Services, RESTful web services, Web Services Description Langugage, Universal Description Discovery and Integration, Service discovery and interfaces, Domain-specific security and privacy architectures, Location bases services, Sercurity Services and Markup languages.