Schoolwide Positive Behavior Support (SWPBS) offers an alternative to reactive and exclusionary school discipline practices. However, the shift to SWPBS requires substantial change in the practices of staff, and many leadership teams struggle to rally staff support for implementation. With a more thorough understanding of staff perceptions, level of understanding, and support for SWPBS, teams may be better positioned to assist staff in the change process. To achieve an understanding of staff perceptions and how they may differ in schools on the basis of level of implementation, the authors directly assessed staff perceptions in seven planning schools and seven implementing schools. Significant differences were found between planning and implementing schools in knowledge of SWPBS, as well as perceptions of behavior and discipline.