This book constitutes the refereed post-conference proceedings of the 7th International Conference on IoT as a Service, IoTaaS 2021, which took place in Sydney, Australia, in December 2021. Due to COVID-19 pandemic the conference was held virtually.The 17 revised full papers were carefully reviewed and selected from 129 submissions. The papers are divided in content-related tracks: Intelligent IoT communication solutions; Social Internet of Things: security, management; Machine learning prediction and recommendation in IoT.