The purpose of this paper is to elucidate school leader education for collaborative school leader by examining the assumptions of Prospective Principal’s Program at Stanford University. It is thought that the point at issue in school leader education in Japan is which is more important, theory or practice. However, the point at issue should rather be what type of school leaders we have to prepare, heroic or collaborative. This paper will focus on Prospective Principal’s Program because this program prepares collaborative school leader and because in designing this program, E. Bridges examined the school leader’s work and the knowledge base of school leader. The Prospective Principals Program offers the Master of Arts degree with a specialization in Administration and Policy Analysis. By comparing Prospective Principal’s program with the former one, I will show the three assumptions of designing of this program. Finally, using the results of analysis of Prospective Principal’s program at Stanford University, I will examine some prospects and issues for school leader education in Japan.