ORGANIZATIONAL CULTURE: A THEORETICAL INVESTIGATION Abstract Organizational culture, which is one of the important factors in the success of an organization, plays a key role in the performance and effectiveness of the organization. This concept affects many factors such as employee morale and productivity, motivation, ability to recruit employees. It is important for businesses to develop and maintain organizational culture in terms of their success both in the short and long term. Organizational culture has been characterized by many authors as something related to the people, the unique quality and style of the organization, and the way things are done in organizations. Organization members take the basic values of the organizational culture such as values, beliefs and norms as a basis in solving the problems they encounter. Therefore, this situation is reflected in the attitudes and behaviors of the members of the organization. In this context, the aim of this study is to provide a better understanding of the concept of organizational culture, based on the theoretical and empirical studies in the literature, to address the importance of organizational culture in terms of businesses by referring to organizational culture models. Keywords: Organizational Culture, Organization Members, Performance and Effectiveness