The study examined the relationship between classroom management and student behavior at Kabami Secondary School in Kisoro District, Uganda. The purpose was to find out the various classroom management practices used by teachers, assess how students behaved while in class, and establish the relationship between effective classroom management and student behavior. The study adopted a descriptive research design, combining both qualitative and quantitative approaches to provide a comprehensive understanding of the research problem. A total of 106 respondents, including the headteacher, Director of Studies, class teachers, prefects, and students, participated in the study. Data were collected through questionnaires, interviews, and observation, and analyzed using descriptive statistics and multiple linear regression. The results revealed that classroom management significantly influenced students’ behavior, with a strong positive correlation (R = 0.801, p < 0.01) and an R² value of 0.642, indicating that about 64% of variations in student behavior were explained by classroom management practices. Effective management practices such as teacher punctuality, clear classroom rules, lesson preparation, consistent supervision, and positive teacher–student relationships were found to promote discipline, cooperation, and academic engagement among learners. Conversely, classrooms characterized by poor organization, irregular teaching routines, and limited supervision experienced frequent misbehavior, absenteeism, and low academic performance. It was concluded that classroom management and student behavior were interdependent, and that disciplined, well-managed classrooms enhanced learners’ concentration, participation, and moral conduct. Teachers who modeled good behavior, provided structure, and maintained fairness were more likely to achieve positive behavioral outcomes among their students. The study further concluded that effective classroom management was not merely about control, but about creating a respectful, engaging, and supportive environment that encouraged responsible behavior and academic excellence. The study recommended that the school administration and education authorities should strengthen teacher training programs on classroom management techniques, ensure consistent enforcement of school and classroom rules, and promote positive teacher–student relationships. Furthermore, schools should integrate guidance and counseling services, involve parents in discipline reinforcement, and provide adequate learning facilities to support effective teaching and learning. Enhancing supervision, motivation, and professional development among teachers was also recommended to sustain discipline and academic performance.