The purpose of this study was to determine the leadership practices needed to improve academic achievement and generate positive change in school organizations. The study was also conducted to provide insight to principal preparation programs and school districts about effective transformational leadership practices. A quantitative research method was used to achieve the survey study. Ninety-two teachers completed the Leadership Practices Inventory developed by Kouzes and Posner. Data was analyzed with the use of descriptive statistics and t-tests. The findings of the study indicate that (a) principals in high performing schools employ all leadership practices more frequently than principals in lower performing schools and (b) inspiring a shared vision and challenging the process are the two practices that have the biggest impact on student achievement. It is recommended that principal preparation programs incorporate Kouzes and Posner's transformational leadership model into their curriculum in order to develop highly qualified school leaders.