| Abstract. Indonesia's ethnic diversity has become a world-recognized identity. There are more than 750 ethnic groups throughout Indonesia from Sabang to Merauke. Every ethnic group has its character and is also an image of a proud cultural system. The Lio ethnic group is one of the ethnic groups on the island of Flores with their traditional ties and values of local wisdom that enrich Indonesia's diversity. One of its values include the local leadership known as Mosalaki. In Sikka Regency, the status of a Mosalaki in the Lio ethnic group is still the central point of the social structure. The Mosalaki are prominent figures in terms of their origins, authority and charisma that are not shared by society in general. In various traditional ceremonial procedures, the Mosalaki have an essential role to play, such as deciding the planting season, land management procedures, marriage procedures, and procedures for preserving and ensuring the wellbeing of people, contact behaviour, the belief system embraced even in the realm of modern politics today. This research was conducted using a qualitative approach as developed by Spradley. The results of the study describe that the role of a Mosalaki is still the focal point of all activities in the Lio ethnic, especially in the modern world today. In Sikka Regency, the Mosalaki is an important part of development efforts.