School-wide positive behavior support (SWPBS) has been implemented in more than 4,000 schools as a means of addressing problem behavior in a systemic fashion. Preliminary outcomes (e.g., office discipline referrals, suspensions) indicate the effectiveness of SWPBS in decreasing school-wide behavior problems and creating a positive school climate. Although the results of a majority of the program evaluations yielded significant findings, there has been a lack of measurement of treatment fidelity, possibly due to the absence of expedient, effective assessment tools. This article describes the theoretical background and development, including a qualitative pilot study and psychometric properties, of the School-wide Benchmarks of Quality (BoQ; Kincaid, Childs, & George, 2005), a tool intended to measure the implementation of SWPBS. Descriptive data on the instrument, including internal consistency, test-retest reliability, interrater reliability, and concurrent validity, were collected and analyzed. Results indicate that the BoQ for SWPBS is a reliable, valid, efficient, and useful instrument for measuring the fidelity of implementation of the primary or universal level of PBS application in individual schools. Future considerations for evaluating the psychometric properties of the BoQ include extending the data collection and analysis to many more schools across multiple states. (Contains 2 figures and 6 tables.)