This book constitutes the refereed post-conference proceedings of the 6st International Conference on IoT as a Service, IoTaaS 2020, which took place in Xi'an, China, in November 2020. Due to COVID-19 pandemic the conference was held virtually. The 69 revised full papers were carefully reviewed and selected from 136 submissions. The papers present two technical tracks and three workshops: The Second Workshop on Edge Intelligence and Computing for Iot Communications and Applications, the Workshop on Satellite Communication Networks for Internet of Things, the Workshop on Satellite Communications