Effective classroom management is central to teaching quality, yet teachers in resource-constrained Nigerian secondary schools frequently work under conditions characterised by overcrowded classrooms, inadequate instructional materials, heavy workloads and limited professional support. This study examined how principals’ directive and supportive leadership styles influence teachers’ adoption of positive classroom-management practices in selected public secondary schools in North-Central Nigeria. A convergent mixed-method design was adopted. The quantitative component employed a correlational survey with 520 teachers, while the qualitative component involved semi-structured interviews with 20 teachers and 10 principals. Data were collected using the Principals’ Leadership Styles Scale and Positive Classroom Management Practices Scale. Quantitative data were analysed using descriptive statistics, Pearson correlation, hierarchical regression and mediation analysis, while qualitative data were analysed thematically. The findings showed that supportive leadership had a stronger positive relationship with teachers’ adoption of positive classroom-management practices than directive leadership. Supportive leadership was positively associated with teacher autonomy, collaborative problem-solving, preventive behaviour management and positive teachers – student relationships. Directive leadership demonstrated a positive but weaker association with classroom-management consistency, particularly where teachers required clear behavioural expectations and procedures. Mediation analysis indicated that teacher instructional self-efficacy partially mediated the relationship between supportive leadership and positive classroom management. Qualitative findings suggested that supportive principals encouraged experimentation, professional confidence and collaborative problem-solving, whereas excessive directive leadership was associated with compliance without ownership. The study concludes that resource-constrained schools require principals who combine clear direction with relational support rather than relying predominantly on command-and-control leadership.

Keywords: Directive Leadership, Supportive Leadership, Principals, Classroom Management, Teacher Self-Efficacy, Resource-Constrained Schools.