Abstract This study examines the impact of ethnic politics on national identity in post-colonial South Sudan. Despite independence in 2011, South Sudan has continued to experience deep ethnic polarization, weak institutions, and recurrent conflict. The study was guided by three objectives: to assess how ethnic-based political mobilization affects national identity, to identify the key challenges posed by ethnic politics to national unity, and to propose frameworks for fostering an inclusive national identity in South Sudan. A mixed-methods research design was employed, combining both qualitative and quantitative approaches. Primary data were collected through structured questionnaires administered to 85 respondents and semi-structured interviews with key informants including government officials, political party leaders, civil society representatives, and university scholars. Secondary data from academic literature, policy documents, and government reports supplemented the field findings. Multi-stage sampling techniques were adopted to ensure diverse representation, while data were analyzed using descriptive statistics for quantitative responses and thematic analysis for qualitative insights. The findings indicate that ethnic-based political mobilization significantly undermines citizens’ sense of national belonging, as political leaders often prioritize ethnic constituencies over national interests. Over 80% of respondents confirmed that ethnic politics fuels political instability, encourages exclusion, and weakens trust in government institutions. Ethnic favoritism in appointments and resource allocation was identified as a major barrier to inclusivity, fostering resentment and marginalization. Furthermore, ethnic competition was found to fuel violent conflicts, erode social cohesion, and obstruct state-building efforts. Despite these challenges, the study revealed strong public support for inclusive frameworks that could strengthen national identity. Respondents emphasized inclusive governance, civic education, inter-ethnic dialogue, and multi-ethnic political party representation as viable strategies for fostering unity. The study concludes that addressing the negative impact of ethnic politics requires both structural reforms and cultural transformation. It recommends institutionalizing inclusivity in governance, promoting equitable distribution of resources, expanding civic education, and reinforcing national symbols and reconciliation initiatives as pathways to build a cohesive South Sudanese identity.