In Ethiopian politico-legal history, since 1995 the federal constitution was built on the principle of accommodating diversity and shared distribution of power and responsibilities between the central, regional and local governments. However, disagreements on the effective protection of the rights of ethnic and occupational minorities are tremendous. Both the Federal and regional governments of Ethiopia are overlooked constitutional guarantees to minority ethnic groups which led to discrimination, alienation and marginalization. In this regard, the regional constitution of the Southern Nations, Nationalities and Peoples (SNNP) also faces couples of pitfalls in entertaining and ensuring ethnic and occupational equality of groups within its legal and constitutional realms. The major purpose of this study was therefore to explore the causes and consequences of marginalization and social inequality of the Manja ethnic minority, in reference to the SNNP’s constitutional powers and practices and the endeavors made so far to address the problem. To achieve the target of the study, multidisciplinary approaches such as web-based evidences, published and unpublished research outputs and personal observation have thoroughly employed. Moreover, the social exclusion theory and rights based perspective of exclusion and marginalization have used to analyze and discover the real picture of the problem in the Sothern Nations Nationalities and the peoples region of Ethiopia.