The Nigerian state since political independence in 1960 has been basking in the euphoria of ethnic politics and electoral violence. Each ethnic nationality in Nigeria has its own culture, interest, aspiration, language and faith and these factors seems to affect the socio-economic and political fate of each group, make identification with the nation a problematic task and exacerbate the difficulty in attaining credible elections a true democracy in the society. Against this backdrop, this study examined the relationship and the effect of ethnic politics on electoral violence in the south-south geopolitical zone of Nigeria. A cross sectional research designed was adopted and data was collected via a survey of six hundred (600) respondents. Data collected were analysed using simple percentages, correlation, and linear regression analysis with the aid of statistical package for social sciences (SPSS) version 23. The results of the study revealed that there is a significant relationship between ethnic politics and electoral violence in the south-south geopolitical zone of Nigeria. The study also showed that ethnic politics exerts a positive and statistically significant impact on electoral violence in the south-south geopolitical zone of Nigeria. Based on these findings, the study concludes that ethnic politics has significant influence on electoral violence in Nigeria. The study therefore recommends, among other things, that Nigerian political leaders should place Nigerian citizens at the centre of their political project without recourse to ethnic chauvinism and the acquisition of political power as a means for serving the collective interest of the citizens irrespective of their ethnic origin. This will go a long way to reduce electoral violence in Nigeria, especially in the south-south geopolitical zone.