The Gumuz are one of the indigenous peoples have settled in the Matakkal Zone of Benishangul Gum~z National Regional State in Northwestern Ethiopia. For a long time, they were victims of slave trade by the rulers of Christian kingdom and local regional lords up to the twentieth century. They maintained both hostile and peaceful relations with the neighboring non- Gumuz .communities.· Their hostile relations with them in the region can be attributed to the past experience of slavery, maladministration, competition over land resources and heroism. Despite the conflict, they could interact with non-Gumuz ethnic groups. They resolved conflicts by the P~ctceful institution of Michu, Harma Hodha, Wada), Mijitn, Anguatsaum and Abal<fj. This thesis focuses on inter- ethnic relations of the Gumuz communities based on the social organization. In the relations, there was conflict within Gumuz society. Their conflict was instigate~ by the problems related to marriage, abducting girls, elopement, adultery, incest, JCief in evil eye, Ceii« (Witch doctor}, deliberate killings for heroism, competitions over the use of land resources, insults and failure to pay back debts. The cyclical intra-clan and inter-clan conflicts can be resolved through Mangima institution. Mangima institution played a significant rote in resolving conflicts as well as contributed to the establishment of peaceful relations within Gumuz communities in each districts of Matakkal Zone. The Cumuz were also affected by the 1984-85 resettlement program. The program had affected their shifting cultivation and coping strategies such as hunting, gathering, fishing and honey collection. This could arouse conflict among host communities and the state sponsored settlers . After a Jong time of tension, they had resolved their problems through Wada) bond of friendship.