This book constitutes the refereed proceedings of the 23rd International Conference on Web Engineering, ICWE 2023, held in Alicante, Spain, during June 6-9, 2023. The 18 revised full papers and 7 short papers presented in this book were carefully reviewed and selected from 77 submissions. They are organized in topical sections named: architecting the web in the cloud continuum; machine learning for web engineering; IoT and WoT engineering; user privacy engineering; user behaviour characterization; user centered technologies; tools and techniques for advanced web engineering; and web engineering practices and experiences.