Organizations have to be in a relationship with the public and maintain this relationship in a balanced way in order to make progress and maintain their existence. Organizations conduct their relations with the public through communication tools and methods. Communication activities of a particular organization are basically identied as public relations, advertising or propaganda. Which of these identicaitons characterizes the communication activities of the organization is determined by the attitude and opinions of the organization towards the public. If the organization prioritizes its own goals and interests, exposes the public to certain impositions and adopts an authoritative form of communication in order to obtain the desired behavior from them, propaganda is preferred. On the other hand, if the organization carries out communication activities aimed at obtaining the desired behavior from them in line with its own interests and goals by meeting the needs of the public, relations with the public in that organization are mostly carried out within the framework of advertising. On the contrary, if the interests and goals of the public are as important and taken into account as those of the organization, if the public inuences the organization as well as the public, then the relations of that organization with the public are carried out with the principles of public relations. The aim of this study is to ground this character of public relations, advertising and propaganda epistemologically with Talcott Parsons' Social Action Theory. According to this aim; organizations were considered as a society, and it was concluded that propaganda activities in organizations where the cultural system is dominant, advertising activities in organizations where the social system is dominant, and public relations activities in organizations where these two subsystems are dominated by the personality system characterize the organization-public relations.