This book constitutes the proceedings of the 20th International Conference on Web Information Systems and Applications, WISA 2023, held in Chengdu, China, in September 2023.

The 43 full papers and 9 short papers presented in this book were carefully reviewed and selected from 213 submissions. The papers are grouped in topical sections on Data Mining and Knowledge Discovery, Recommender Systems, Natural Language Processing, Security, Privacy and Trust, Blockchain, Parallel and Distributed Systems and Database for Artificial Intelligence..