This study examined the role of state peacebuilding institutions in managing communal conflicts in Nigeria, using the 2023 USIP-supported mediation agreements in Kaduna State as a case study. The study was guided four specific objectives and four research questions. The study adopted a qualitative case study design. The population consisted of individuals directly or indirectly involved in the peacebuilding process such as officials of the Kaduna State Peace Commission, traditional rulers, religious leaders, representatives of community-based organizations (CBOs), women and youth leaders, and USIP representatives. A purposive sampling technique was used to select 30 key participants who had firsthand knowledge or direct involvement in the mediation process. The primary instruments for data collection were Key Informant Interviews (KIIs) and Focus Group Discussions (FGDs). Data collected from KIIs and FGDs were transcribed verbatim and analyzed thematically using NVivo qualitative data analysis software. Findings revealed that state institutions, particularly the Kaduna State Peace Commission, played central roles in coordinating mediation efforts, facilitating inclusive dialogue, and establishing Local Peace Committees (LPCs). The mediation agreements led to a significant reduction in violent conflicts in Southern Kaduna and enhanced community engagement in peacebuilding. Traditional leaders, women, and youth were actively involved, although challenges of unequal participation still existed. The study also found that the sustainability of the peace outcomes depends on continuous institutional support, political will, and community involvement. Based on the findings, the study recommends strengthening institutional capacity, promoting inclusive participation, institutionalizing early warning systems, conducting regular monitoring, and enhancing multi-stakeholder collaboration. These steps are essential for consolidating peace and preventing the resurgence of communal violence in Kaduna State and other conflict-prone regions in Nigeria.