Operational excellence has become a popular strategy within many large companies and it aims to raise the competitiveness by increasing the organizational efficiency in areas such as faster time-to-market, reduced costs, improved quality and reduced supply lead time, which can have a major positive impact on company profits. By understanding how leadership at each level in the company can have a positive impact on an organizations success when implementing an operational excellence strategy, the organization can take actions accordingly. This thesis studies and compares three different units from two large Swedish organizations in order to find leadership aspects that have an affect on leader’s ability to drive operational excellence in the organization. Two of the studied cases show a mix of transformational and transactional leadership while the third case only uses transformational leadership. The study shows that a transformational leadership style is more efficient for driving operational excellence. It is also clear that different leadership abilities are needed depending on the leaders’ position as well as the complexity of the organization. For senior leaders that need to act through other leaders it is more important to be assertive and self-confidence, while first level line managers need to have a higher level of emotional intelligence, warmth and authenticity due to their close relationship with the employees.