This study examined sources of conflict and how conflict affects student‟s performance in Ilemela public secondary schools. The study adopted a mixed method research approach. A sample size of 480 respondents recruited from 24 public secondary schools in Ilemela the district were involved in this study. Data was collected via interview and questionnaires and was analyzed using computer software, that is, Statistical Package for Social Sciences (SPSS) and Microsoft Excel. Descriptive statistics were used to analyze the data and reported using frequency tables, graphs, pie charts and percentages. The findings indicated that major sources of conflicts were unimpressive conditions of service, administrative incompetence‟s of the heads of school, embezzlement of funds, indiscipline in the parts of students, teachers or administrators and inadequate resources. Based on the findings, the study recommends those responsible in ensuring elimination or improvement of conditions that contribute to conflict in the schools to take both short term and long term action. The study also recommends those concerned to introduce trainings on conflicts resolution strategies in schools to assist in management of conflicts. This would mark the reduction of conflicts in the schools and improved student‟s performances.