Purpose: The purpose of the study is to identify the task and relationship behaviors and processes used by school leadership teams identified as effective. In addition, the study will identify similar characteristics across effective teams. Methodology:The participants in the present study were 12 school leadership teams from highly effective elementary schools in Southern California. Participants responded to a 20 item survey (Team Effectiveness Inventory, Hoevemeyer, 1993) to identify highly effective school leadership teams. The highly effective teams participated in the recording of a leadership meeting to analyze their process and behaviors relating to task and relationship of the Group Development Matrix (Jones & Bearley, 1986). Findings: Examination of qualitative data from the six highly effective elementary schools indicated that effective teams progressed through the Group Development Matrix (Jones & Bearley, 1986) and demonstrated processes and behaviors to address each dimension. Secondly, the effective teams were dependent on the approach to leadership by the school principal. The six school principals lead the teams' progression through the matrix resulting in highly effective school leadership teams. Additionally, team development must be explicitly taught to develop effective school leadership teams. Conclusions: The study supported the fact that highly effective teams progress through the two dimensions of group development matrix. The role of the school principal is vital to the success of the school leadership team. Programs for development of effective school leadership teams are essential to public education. Recommendations: Further research is advised to: identify effective and ineffective school leaders, and then compare the effectiveness of their leadership teams, a comparison study which compared significant differences between effective and ineffective school leadership teams would further identify necessary areas for professional learning, explore the same domains of this study but at the secondary level, and lastly to study programs pre-established for developing school leadership team to see if the correlate with the stages of group development. [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://www.proquest.com/en-US/products/dissertations/individuals.shtml.]