Preschool environments can be critical to academic success and risk reduction but disruptive behaviors can have significant and lasting negative effects on students as well as teachers. These behaviors may be pervasive in some classrooms and effective interventions are needed. A combined delayed multiple baseline and withdrawal design across a teacher's two classrooms (a.m. and p.m.) was used to monitor the effectiveness of an interdependent group contingency procedure used during circle time, a key learning activity. Results from the morning and afternoon half-day classrooms led by the lead teacher generally indicated that the intervention was effective at decreasing student disruptions. In addition, outcomes demonstrated increased student engagement and improvements in more positive teacher attention compared with negative attention. Teacher-directed instruction, on average, increased in the morning classroom during intervention conditions and remained high across conditions in the afternoon classroom. (author abstract)