Although there were ethnic based political organizations since 1970’s , the introduction of ethnic federalism in the post 1991 period opened a wider space for the mushroom growth of ethnic based parties in Ethiopia. Many of the political parties that are competing in the current Ethiopian politics are ethnic based. Their formation empowered many ethnic groups to have proper political representation at national and regional level. However, their exclusive policy is affecting the healthy functioning of the Ethiopian politics. Therefore, the main objective of this study was to assess the implication of OLF and NaMA on Ethiopian national unity. To reach on finding, the researcher used Qualitative case study design through comparative strategy. Both primary and secondary data sources were extensively used for this study.Key informants for interview and focus group discussion were selected through purposive, event and snowball sampling techniques. The collected data was analyzed by blending both thematic and discourse analysis methods together. The finding of the study indicated that OLF is a threat for national unity due to its ambivalent position to coexist peacefully, siege mentality attitude towards other ethnic groups and its participation in human right violation and illegal income generating activities. On the other hand, NaMA has created a mixed effect on Ethiopian unity. On the one side, it helps to maintain the power equilibrium between the secessionist and unionist forces. Its position on the issue of Addis Ababa and other national economic policies is Ethiopian oriented. NaMA’s initiation to amend the FDRE constitution, which is perceived by many scholars as a problematic document, is taken as a privilege for Ethiopian unity. On the other side, belonging the perceived core values and identities of Ethiopia as the identity of the Amhara people alone and emotion laden speeches of the party leaders to portray the Amhara people as the “creator of Ethiopia” erode the sense of unity as it served to diminish the role of other ethnic groups in state making. Its policy to make Amharic the national language of the state created a dissent on others as many rivalry ethnic groups compete for supremacy.As a result, the researcher recommends the need to revise the state structure, government institutions and other legal documents that endangered national unity. Key words: OLF, NaMA, Oromo, Amhara, National Unity, National Consensus