Good leadership of the school plays an important role in raising the students' academic achievement in Nigeria. This study (leadership styles, types and students' academic achievement in Nigeria) examined whether the principal's leadership styles-types, his gender, highest educational qualification and experience as a principal do play their contributing influence in the school performance as well as students' academic achievement. Finally, the study intends to propose the leadership model for the Nigerian school principals. The research design used is a quantitative descriptive cross-sectional survey research design. Theoretical or educational gap, locational gap, and the approach gap were identified. In the research process, the researcher utilized two inventory questionnaires and the field form that was validated by a panel of experts. Stratified random sampling with 480 teachers and 60 principals employed, but only 380 teachers and 57 principals responded. ANOVA, z-test, correlation, percentage and mean were used. Principals' experience and his highest qualification are significant.