Providing a comfortable environment with good indoor air quality for the occupants is a high priority for a building. Ventilation is definitive to indoor air quality and one of the key preliminary interests is to provide a comfortable and healthy indoor environment for occupants. In this lecture, after an introduction of thermal comfort, ventilation parameters, the human response to the thermal environment, some important standards in these fields are explained. Moreover, the influence of ventilation parameters on thermal comfort and occupant behavior in offices is also discussed.