While the need for systemic change in physical education has been well documented in the literature (Rink, 2002; Rink & Williams, 2003; Siedentop, 1987; Stroot, 1994), physical education has largely not been successful at systemic reform and has for the most part been excluded from large-scale efforts to reform education (Ward & Doutis, 1999). In 2001, South Carolina chose to be a part of a state reform effort by establishing a physical education assessment program based on student achievement. Although it has been difficult to identify generic indicators contributing to overall school effectiveness and successful educational reform, studies in school effectiveness (Cuban, 1984; Dow & Oakley, 1992; Edmonds, 1982) and in school reform (Fullan, 2001) have consistently identified the role of the principal as a critical contributing factor to school effectiveness and to reform implementation success. The school principal would be expected to be a major player in physical education reform efforts as well. The purpose of this study was to describe the perceptions and support of South Carolina high school principals concerning the South Carolina Physical Education Assessment Program (SCPEAP). Seventy-seven high school principals completed an on-line survey describing their awareness, perceptions and support of the assessment program. Eight principals representing different levels of support were interviewed to gain a deeper understanding of information and eight teachers were randomly selected to participate in a follow-up interview in an effort to verify principals' responses. Quantitative data from the survey were analyzed using frequencies and descriptive statistics. Qualitative data from open-ended responses and interviews were also analyzed. The results revealed that principals were generally positive and supportive of the SCPEAP although support levels varied. The majority believed the assessment program has had a positive impact on physical education programs in their schools. All principals interviewed stated it had brought about positive program, instructional, and student changes. Principals did express concerns about certain implementation issues such as the overall process being too “involved” and too time consuming. Although principals reported a high level of awareness of the program in general, they lacked a comprehensive understanding of program procedures and the different components of the initiative. By and large, principals did not take more active roles because of the assessment program but indicated they would become highly involved if the program became a mandate and was publicly reported. Keyword(s): assessment, high school issues, physical education PK-12