Organization is present in every aspect of a person’s life, from birth to death. Taking into consideration various time frames in organizational science development, this paper begins with addressing three theories of organization - classical, neoclassical, and modern. As organization changed over the years, the way it has been approached followed the change as well. Being one of the most important and challenging managerial roles, leadership is a key element on which business success depends. Management systems i.e., leadership theories, will be approached in four basic groups, namely: trait theory, behavioral theory, contingency theory, and modern theory. This paper will examine and try to detect the crucial differences between these leadership theories and select the best theory for all organizations, if such a theory truly exists. Secondary data sources, description methods, compilation methods, synthesis methods and induction methods were used to write the final paper and prove the set hypotheses. The crucial difference between classical and modern models lies in the focus on an individual, but also the power and the position the leader holds, decision making, and the relationship between leader and its employees. Classical models are focused on task completion, resulting in maximization of business while the people, within this theory’s frame of thought, are considered replaceable. On the other hand, modern models see people as the most valuable resource since they are the ones making their organization distinctive. Since no two people think and perform tasks the same, no two organizations are the same either, and the increasingly dynamic environment will play a role in the merger of the two leadership styles. That way, every organization will create their own tailor-made leadership style that will influence the success of leadership and the business itself.