The study explores the roles of civil society actors in peace building in Ethiopia with particular reference of Borena-Guji conflict. Particularly in Ethiopia, there are few legally recognized civil society organizations that involved in the area of peace. The study employed a qualitative research method and case study design through involving both primary and secondary data sources. Purposive sampling method also employed. The required primary data were collected through semi structured, personal observation and document review. To analyze the data qualitative thematic analysis was used. The finding of the study reveal that civil societies are playing a role in peace building in Borena-Guji conflict through providing trainings about the importance of peaceful conflict resolution and the impact of conflict. They also organize meeting and dialogue sessions to discuss on the root causes of the Borena-Guji conflict and provide Aids Materials for victims of conflict and reintegrating internally displaced persons as a result of the conflict. Civil Societies have made progress through the establishment of joint peace committee, reconciliation, rebuilding of social relationship, compensating victims of the conflict, return of internally displaced people and bringing attitudinal changes. Moreover, civil societies also work in cooperation with governmental bodies to achieve lasting peace between the two communities. Despites these realities, civil societies are facing various challenges like shortage of aid Materials, the prevalence of non-religious peoples, and Complexity of the cause of conflict. In sum up, as compared to the internationally accepted civil societies function in peace building, their role in peace building in Ethiopia particularly in the study area is limited.