This study examines the influence of emotional intelligence (EI) on classroom behavior management, peer interactions, and academic outcomes among secondary school students and teachers. Using a sample of 150 teachers and 500 students across five high schools in Tanzania, the research employed a quantitative approach, integrating EI assessments with classroom observations. Statistical analysis revealed that teachers with higher EI scores (M = 82.5, SD = 7.2) significantly correlated with better classroom behavior management (r = 0.60, p < 0.01) and enhanced student engagement (r = 0.55, p < 0.01). These classrooms also demonstrated a 10% increase in student academic performance compared to those led by lower-EI teachers (M = 73.8, SD = 8.4). Additionally, students with higher EI scores (M = 76.4, SD = 8.7) exhibited stronger peer relationships and higher motivation to learn (r = 0.52, p < 0.01). These findings highlight the vital role of EI in improving educational outcomes and suggest the need for emotional intelligence training in both teachers and students to foster more positive and effective learning environments.