One proactive approach to aid in reducing disciplinary problems in schools is implementing Positive Behavior Support (PBS) strategies. To successfully implement PBS school-wide, Sugai and Horner (2002a) emphasize a multi-systems perspective, which focuses on school-wide discipline, classroom management, non-classroom settings, and individual students. According to Nelson, Smith, and Colvin (1995) approximately 50% of problem behaviors resulting in discipline referrals occur in non-classroom settings (e.g., hallway, cafeteria). One intervention commonly utilized in non-classroom settings is active supervision. The purpose of the present study was to assess the effects of active supervision on the hallway behavior (i.e., tardies) of students in a rural high school using a multiple baseline across instructional periods. The results show that active supervision decreased frequency of tardies across instructional periods. Also, each active supervision component was assessed, suggesting that all components may not be essential in obtaining student behavior change. Implications and future research are also discussed.