This book constitutes refereed proceedings of the Second International Conference on Smart Technologies, Systems and Applications, held in Quito, Ecuador, in December 2021. Due to the COVID-19 pandemic the conference was held in a hybrid format. The 29 full papers along with 1 short paper presented were carefully reviewed and selected from 104 submissions. The papers of this volume are organized in topical sections on smart technologies; smart systems; smart trends and applications.