Sensing technologies are essential parts of the smart building paradigm. In recent years, an increasing number of research studies are focusing on using sensing technologies to understand the influences of indoor environmental conditions on the occupant’s health and comfort. Such studies provide a critical perspective on improved human-building interactions and optimized building operations. This research aims to provide a systematic literature review of various sensing techniques and their applications in improving occupant well-being. The authors consulted the guideline put forward by the American Society of Heating, Refrigerating and Air-Conditioning Engineers (ASHRAE), ASHRAE Guideline 10-2016, as a framework to categorize different research studies. This research summarizes and discusses both academic and applied studies pertaining to indoor air quality, acoustic comfort, thermal conditions, illumination, odor, and vibrational disturbances. The review results show that, in the built environment, using sensing technologies to mitigate factors disturbing occupant well-being is critical but relevant research is still in its early stage, and most of the current research has focused on indoor air quality and thermal condition. This chapter has identified four main research gaps, 1) cost-effectiveness, 2) sensor range and positioning, 3) data interface and privacy, and 4) occupant expectations and subjective interactions, and provided recommendations for future research.