Thermal comfort has been widely studied from the middle of the twentieth century to the present. From Fanger’s model based on the neutral thermal state and the development of the Predicted Mean Vote (PMV) and Predicted Percentage of Dissatisfied (PPD) indexes to the adaptive approach based on buildings that operate with natural ventilation, several studies set detailed conditions with strengths and limitations. In this chapter, a review from the international to the specific comfort models is established. In this sense, ASHRAE 55-2017 and EN 16798-1:2019 are the two most used models; both are based on international research projects with large databases. The two models present similarities in terms of applicability, however, some differences are analyzed (e.g., categories considered). In an intermediary state, various countries like the Netherlands (ISSO 74) and China (GB/T50785) have developed specific adaptive thermal comfort models, which present sensible differences with the international standards. Moreover, local studies are carried out in Australia, Chile, India, and Romania, regarding specific building types (e.g., social dwellings in Chile) or for certain climate conditions. To sum up, many research studies at different levels of resolution have presented the potential of adaptive thermal comfort models, to better understand the users’ adaptability.