We evaluated the effects of stability balls on in-seat and on-task behavior of students with attention and hyperactivity concerns. A group of 8 students in the 4th and 5th grades was observed 3 times/wk for 12 wk using a single-subject A–B continuous time-series design. We analyzed data collected from standardized measures and classroom observations for mean differences across pre- and postintervention phases. Results of the stability ball intervention revealed increased levels of attention, decreased levels of hyperactivity, and increased time on task and in seat or on ball. Findings from the social validity questionnaire demonstrated that teachers preferred the stability balls over chairs. This study provides additional evidence for the effectiveness of stability balls in the general education classroom for children who exhibit difficulties with attention and hyperactivity.