The two-volume set LNCS 10569 and LNCS 10570 constitutes the proceedings of the 18th International Conference on Web Information Systems Engineering, WISE 2017, held in Puschino, Russia, in October 2017. The 49 full papers and 24 short papers presented were carefully reviewed and selected from 195 submissions. The papers cover a wide range of topics such as microblog data analysis, social network data analysis, data mining, pattern mining, event detection, cloud computing, query processing, spatial and temporal data, graph theory, crowdsourcing and crowdsensing, web data model, language processing and web protocols, web-based applications, data storage and generator, security and privacy, sentiment analysis, and recommender systems.