Concern about school safety has increased in recent years (Sprague et al., 1999), leading to a greater interest in methods such as Positive Behavior Support (PBS), which has been found to be successful at creating safe environments through use of preventive methods and the development of proactive systems for at-risk student populations (Horner, Sugai, & Horner, 2000). School-Wide Positive Behavior Support (SW-PBS) is an efficient and comprehensive application of PBS (Sugai & Horner, 2002). Treatment acceptability, "judgments by laypersons, clients, and others of whether treatment procedures are appropriate, fair, and reasonable for the problem or client," (Kazdin, 1989, p. 493) is a variable that has been theoretically linked to intervention outcomes (Witt & Elliot, 1985). The purpose of this study was to examine the acceptability of the universal level of SW-PBS among school principals, and to compare responses between elementary and high school principals. Survey packets were mailed to school principals which included a description of SW-PBS and the IRP-15 (Witt & Elliot, 1985). Results from 99 school principals indicated that elementary school principals rated the universal level of SW-PBS as more acceptable than high school principals. The clinical significance of this difference is questionable given that both groups rated the universal level of SW-PBS as acceptable. A limited sample and poor response rate, however, make the generalizability of these results questionable. Limitations of the study and needs for future research are provided.