This research aimed to find out the extent to which the instructional leadership style had been adopted by the principals in some Lebanese intermediate public schools. A small-scale survey approach was used where a cross-sectional study design was assumed. By sampling extreme cases (five high-performing schools and five low-performing ones), the researcher was able to reveal the differences that existed in the principals' leadership styles in the two sets of schools selected. To achieve her objective, the researcher analysed the quantitative data collected from questionnaires administered to 203 teachers, in addition to the qualitative data collected from interviews conducted with principals using a semi-structured interview schedule. Principals in the schools investigated were found to assume climate-related functions more than the technological ones under the instructional leadership style. Both sets of functions were significantly performed better by the principals in the high-achieving schools in comparison with the principals in the low-achieving schools. The researcher ended up by recommending short-term and long-term remedies to enhance the way leadership is exercised and thus enhancing the teaching's quality in Lebanon. (Contains 8 tables.)