Internet of Things (IoT) has become a significant topic of interest in recent years. Billions of everyday devices will be connected and new forms of interaction grow with this new paradigm. However, the future role of IoT in regarding to inclusion in smart environments is not well defined yet. Further studies are still needed to investigate whether these technologies will be an enabler or whether it will introduce more barriers. In this paper, we conducted a systematic mapping to provide an overview of how accessibility has been considered in the development of IoT systems. The results show that the community has presented Assistive Technology solutions based on IoT resources and a lack of studies addressing accessibility and user studies in IoT projects. Therefore, the findings provide an overview of current research in IoT, as well as give implications for new research opportunities.