Given that principals play a role in setting school climate, this paper focuses on how this actually happens. First, the paper explores different criteria and variables as possible frameworks for defining the term "climate." This task is complicated by problems in identifying consensus findings due to weak variable definitions and lack of reliable, valid measures. Next, the databases and conceptual frameworks used to relate the principal's role, school climate, and effects are discussed. These frameworks are then employed to describe three different roles (responder, manager, and initiator) that principals can asume as change facilitators, along with brief descriptions of the types of climate likely to result. Responder style principals, who attend to the present and neglect long-range goals and alternative directions, can foster a rough atmosphere with fuzzy logistics and inefficient management practices. Manager style principals organize efficiently, support teachers well, overprotect them from outside pressures, and cushion the arrival of innovations. When committing to implementation, manager-principals are smooth facilitators in terms of logistics, resources, and innovative procedures. Initiator-principals are skilled at administrative procedures and at pushing students and teachers to excel. They have a strong future vision, support teachers' collaboration, and carry on meaningful dialogs related to student needs and achievements. Implications of the three roles for school improvement are also discussed. Included are 16 references and 6 figures. (MLH)