Influence of principals’ instructional leadership and teachers’ efficacy on students’ performance in secondary schools in the Wolaita Zone, South Ethiopia

School leadership and teacher efficacy are the most important factors in improving student performance in resource-poor region, where educational disparities impede the achievement of Sustainable Development Goal 4 (SDG 4) on equitable education. This study explored the association between principals’ instructional leadership (PIL), teacher self-efficacy (TSE), and students’ performance (SP) in secondary schools in the Wolaita Zone, South Ethiopia. Adopting a concurrent mixed-method design, the study comprised 369 respondents (teachers, department heads, unit leaders, and students) from 22 secondary schools, using proportional random sampling. Data were collected through questionnaires and semi-structured interviews with eight school principals. Pearson’s correlation analysis revealed significant positive relationships between PIL and SP (R = 0.78) and between teachers’ efficacy and SP (R = 0.88). The results show that collaborative and teaching-focused leadership practices increase teachers’ confidence and efficacy, resulting in higher student achievement. This study shows that school leaders play a crucial role in enhancing educational outcomes in resource-limited settings study area. By demonstrating how successful leadership can influence teacher motivation and learning among students, this study supports SDG 4 by adopting inclusive and equitable quality education. This implies that the strategy of investing in strong instructional leadership and teacher support in under-resourced rural schools is scalable to minimize educational disparities and enhance the learning outcomes. In particular, building teachers’ capacity through collaborative instructional leadership in settings such as the Wolaita Zone could eliminate achievement gaps and fulfill the inclusive lifelong learning objectives of SDG 4. Based on this evidence, specific policies to develop the capacity of school leadership and teacher development have the potential to promote equity in education and sustainable development in a similar context in rural Ethiopia and the rest of the world, with inputs to the global effort to achieve quality education in the future.