<p>Middle school teachers often encounter more significant challenges in behavior management compared to their elementary counterparts. This is particularly true for middle school art teachers, who may lack the necessary skills for effective behavior management. To address these challenges, Class-Wide FIT (CW-FIT) offers a positive behavioral intervention designed to teach and reinforce on-task behavior in classroom settings. With CW-FIT, teachers instruct students on specific behavioral expectations and provide feedback and rewards for meeting those standards. We investigated the effectiveness of CW-FIT in a middle school art class, involving one teacher and 36 students, using a single-subject ABAB withdrawal design. Data were collected on student on-task behavior, teacher praise, reprimands, implementation fidelity, and social validity. Results indicated that the teacher’s fidelity to CW-FIT components was adequate, but at times below targeted levels—particularly regarding behavior-specific praise and praise-to-reprimand ratios. Nonetheless, observational data showed increases in student on-task behavior during intervention phases, and the teacher and students generally rated CW-FIT as socially valid. The findings suggest that, although implementation fidelity was not uniform, CW-FIT has the potential to positively influence classroom behavior in middle school art settings, but further research is needed to clarify the relationship between fidelity levels and behavioral outcomes given the variability observed.</p>