Political instability is a result of overall social, political, ethnic, or national disintegration and unrest. Historically, Ethiopia is riddled with intra and interstate conflicts. Political instability also increases from time to time. Especially since 2018, it has become a serious issue. The main purpose of this study was to investigate the causes and consequences of political instability in Ethiopia since 2018 taking the bordering areas of the Amhara and Benishangul Gumuz regions as a case. The study adopted a qualitative research approach with a case study research design. Both primary and secondary data were employed. Primary data were collected through in-depth interview. Secondary data were collected from published and unpublished materials. The researcher employed a purposive sampling technique to select the participants of the study. The data collected through different instruments were analyzed by using thematic analysis. The findings of the study revealed the internal and external causes of political instability in the bordering areas of the two regions. The internal causes of political instabilities include conflict, institutional and administrative weakness, historical deviation, BGRSC, expansion of rebel groups, expansion of illegal weapons, and political elite monopolization. The external causes are also pressures of Sudan, TPLF, and OLF. The consequences of political instability are immense damage in all aspects. The study concludes that in these five years since 2018 in Amhara and Benishangul Gumuz region has experienced unprecedented, intense, complex, and multidimensional political instability. Finally, the researcher recommended that the concerned bodies make a clear and strong institutional framework and administrative capacities at all levels, ensuring democracy, upholding the rule of law, prosecuting criminals and make the right decision, controlling the expansion of rebel groups and weapons, finding the truth, and strengthening the relationship between the two regions communities at all level.