The high stakes testing and school accountability movement are steadily increasing at a staggering pace. Improving student outcomes through standards-based reform has become an ever growing and urgent focus for school leadership. The continued study of leadership within the context of our educational systems remains an area to study as it contributes to the capacity of teachers within the schoolhouse. The leadership practices that influence collegial trust and building culture were examined. More specifically, the primary purpose of this study is to examine the effect between the leadership behaviors of Illinois certified public school principals and to what extent if any they may have on teacher-teacher trust. Participants in this study were Illinois public school principals from across the state of Illinois along with their respective faculty members. School principals were chosen from an available database of school principals obtained from the Illinois State Board of Education. The essential practices of transformational leadership: modeling, inspiring, challenging, enabling and encouraging were examined. This quantitative correlational study with regression analysis hopes to further inform our knowledge of the specific leadership practices that contribute most heavily to teacher-teacher trust. No significant relationships were measured between the principals' transformational leadership practices and teacher-teacher trust. Additionally, conclusions and additional areas for future study were discussed. [The dissertation citations contained here are published with the permission of ProQuest LLC. Further reproduction is prohibited without permission. Copies of dissertations may be obtained by Telephone (800) 1-800-521-0600. Web page: http://bibliotheek.ehb.be:2222/en-US/products/dissertations/individuals.shtml.]