Numerous factors influence supervision and professional/staff development of, by, and for administrators, leaders, teachers, and other staff in schools with diverse student populations. Some of these factors include the context; the stated aims and objectives of the school or district; the conception(s) of adult learning employed; the nature of the learners (both adults and students) as understood by those who lead the school and the district; and the resources available—including the time, experience, and skill level of the supervisor or administrator tasked with developing and leading such supervision and professional development efforts. This entry examines the training (i.e., professional development) and supervision by and for leaders and other staff in schools with diverse student populations and the factors influencing such programs.