Over the years, students of Catholic High/Senior secondary schools in Edo state, Nigeria have maintained a significantly higher level of academic achievement than their counterparts in public schools in the state. This development has not only been a cause of serious concern for parents of students who attend public High/Senior secondary schools and the government that runs them but also a critical issue of interest for Catholic leaders as they strive to maintain and improve upon the high level of students' academic achievement in their schools.

This study attempted to explain if and how principal leadership within the specific context of Edo state, Nigeria and the religious culture of the principals is a significant factor in this development. In so doing, the researcher studied the principal leadership of four high performing Catholic high/senior secondary schools in Edo state, Nigeria. From these schools, the researcher sampled sixteen research subjects consisting of four principals and twelve teachers who participated in the study. To elicit data for the study participants were engaged in in-depth interviews sessions. Also, some relevant school documents were retrieved and analyzed and direct observation exercise in the schools was conducted.

In the critical analysis of the collected data, the study found that: 1) that the principal leadership of the four schools of study constituted significant and critical factor to students learning and their academic achievement, 2) that the preferred leadership style of the principals in majority of the schools studied was the democratic or the shared leadership style, 3) that the impact of the local and religious culture on the principal leadership of the schools of study was varied and not neatly determined, 4) that the sustenance of teachers' classroom effectiveness, the level and availability of professional development and the quality and sustenance of the healthy culture believed to inspire better learning and higher academic achievement levels in the schools were closely linked with the principals' leadership and their leadership style.