The students’ discipline plays a significant role in the improvement of academic performance. However, any lack of students’ discipline, significantly affect negatively the level of students’ discipline. The purpose of this study therefore was to establish the relationship between students’ discipline and academic performance in secondary schools in Rwanda for advanced level studying-French-English Kinyarwanda in Rusizi district. The study adopted correlation research design while structured questionnaires, interview guide and desk review were used as data collection instruments. The target population was 283 respondents. The sample size was 166 obtained by the use of Yamane formula. The sample was obtained by the use of simple random and stratified sampling techniques. Questionnaire, interview guide and desk review were used to collect the data. The findings revealed that there is a statistical significant high degree of positive relationship between students’ discipline and academic performance. It was revealed that regular class attendance, respect of school rules and regulation and being given punishment among students create a positive change in students’ academic performance. The study recommended that the government should design effective policies and discipline guidelines. The head teachers should ensure the suitability of a set of rules and regulations in the least performing schools and there is a need to ensure students punishment management and adequate administration of school rules and regulations. Students should respect and comply with school rules and regulations through punctuality, demand of permission, constant attendance, doing homework at time, respect to teaching staff and school management personnel. Keywords: Students’ performance, students’ discipline, secondary schools, Rwanda