This research investigates the correlation between ethnicity and voting in Nigeria from 2015 to 2023, employing a qualitative approach to elucidate the influence of ethnicity on voting patterns, administrative systems, and their contributions to political unrest. The research posits that ethnic-based voting reinforces exclusionary politics and exacerbates post-election disputes, while biased administrative systems undermine state legitimacy, thereby fueling civil unrest. The central research question addresses how ethnic diversity has contributed to political instability in Nigeria during the specified period and evaluates the extent to which institutional frameworks and policies have not mitigated ethnic tensions to promote political stability and nation-building. The timeframe of 2015 to 2023 is particularly significant, marking the first instance in the history of Nigeria where an incumbent president was ousted prior to securing a second term, with ethnicity playing a pivotal role in galvanizing electoral support.