This study examined teachers’ emotional intelligence and students’ academic performance and behaviour in selected public secondary schools in Nigeria. Specifically, it assessed teacher self-awareness, self-regulation, empathy and social skills and their relationships with student motivation, classroom behaviour, academic engagement, academic performance, psychological wellbeing and overall positive outcomes. The study was anchored on Social Learning Theory and Emotional Contagion Theory and adopted a quantitative cross-sectional correlational design. The analytical sample comprised 234 SS2 students representing Nigeria’s six geopolitical zones, with student gender and school type included as controls. Study constructs were measured on five-point Likert-type scales. The data pattern showed consistently strong positive associations between teachers’ emotional intelligence and student motivation, behaviour, engagement, academic performance, psychological wellbeing and overall positive outcomes. The observed pattern was also consistent with a mediation-oriented model in which motivation, behaviour and engagement provide pathways between teacher emotional intelligence and student outcomes. Because the supplied construct scores exhibit unusually high numerical alignment, the findings are interpreted primarily as strong associations rather than definitive causal or independent dimensional effects. The study concludes that emotional intelligence is an important professional teaching competency and recommends its integration into teacher education, continuous professional development, instructional supervision and classroom-management capacity building.