A single-case experimental design was used to evaluate the effects of the Caterpillar Game, a classroom management system, on disruptive behavior in a general education first grade classroom. A multiple baseline design across settings was used to evaluate changes in student disruptive behavior and teacher praise. When the Caterpillar Game was introduced, increased teacher praise and reduction in student disruptive behavior were observed across all three settings and was sustained 8 weeks later. Teacher satisfaction for the Caterpillar Game was also positive. This study extends the literature on classroom management systems by providing initial support for the effectiveness of the Caterpillar Game, an easy and simple to implement classroom management tool.