Smart cities aim to sustainably increase urbanization, lower energy consumption, improve inhabitants' economic and quality of life, and protect the environment. The idea of smart cities revolves around ICT since it makes it easier to formulate policies, make decisions, execution, and ultimately the supply of helpful offerings. In addition to utilizing digital technologies, the concept of the “smart city” is a response to the political, social, and economic issues that post-industrial civilizations are facing at the beginning of the new millennium. In this chapter, the authors discuss several IoT-based machine learning techniques that are applied, among other things, in the aforementioned domains. Furthermore, a review of the assessments and a report on the lessons learned are presented, with an emphasis on the fundamental role that machine learning techniques should play in internet of things networks.