Abstract
This research explored how principals' instructional leadership influences the job performance of teachers in public secondary schools across Nigeria. Anchored on three research questions and two hypotheses, the study utilized a correlational survey design. A total of 400 teachers were selected from both urban and rural secondary schools in Delta State using a multi-stage sampling approach. Data were gathered through a structured questionnaire, which was validated by subject experts and tested for reliability in a pilot study. The results indicated that instructional leadership practices, such as instructional supervision, provision of educational materials, and professional development for staff, were moderately practised. Furthermore, a significant positive correlation was found between principals’ instructional leadership and teacher effectiveness in areas like lesson planning, classroom instruction, and student evaluation. The analysis also revealed notable differences in leadership practices between principals in urban and rural settings. Based on these findings, the study recommends enhancing principals’ instructional leadership through consistent training, improved access to teaching resources, and supportive policies.