Collaborative teacher teams, whether they are new or have been re-formed over time, require that principals understand how to support and sustain them. To sustain collaborative team structures and support teacher empowerment beyond the first years of an initiative, it is important for principals to understand how these three factors--namely, the nature of teaming; the stages of team development; and the team composition--affect the effectiveness of teams and the capacity of teachers to share leadership for teaching and learning. Understanding these factors can allow administrators to minimize or prevent their negative impact. Here, the author describes these three factors.