The Semantic Internet of Things (SIoT) is an Internet of Things (IoT) extension that uses semantic technologies to improve interoperability and understanding of data generated by connected devices. The SIoT can help in smart health by providing a common language and framework for exchanging and integrating health-related data from various sources. This has the potential to improve the accuracy and efficiency of health monitoring and decision-making, allowing for more personalized and effective health interventions. This chapter outlines the Semantic Internet of Things’ core concepts, specifies its focus areas, and lists its various requirements, difficulties, and uses. Through the presentation of a literature review on Semantic Internet of Things healthcare systems, including challenges, prospects, and current work, we highlight the best outcomes for semantics among IoT systems in healthcare, which can serve as a guideline for future research. The chapter also provides an overview of the use of semantic technologies in healthcare IoT, including new projects, frameworks, and specific ontologies that use semantic technologies to address semantic interoperability and heterogeneity issues.