Active Breaks (AB) are a classroom management strategy to increase student on-task behavior in elementary-aged general education populations. ABs are defined as short bouts of physical activity that take place between academic instructional periods. Research has focused on breaks with a dosage ranging from 4- to 15-min, with demonstrated positive effects. The current study aimed to address several gaps in the literature related to teacher implementation of breaks, dosage of breaks, and assessment of teacher and student acceptability and perceptions of ABs. The impact of teacher-led ABs on student on-task behavior was examined across two 3rd grade general education classrooms through the implementation of a within-subject ABC research design, with each classroom exposed to each of the three conditions. Results of this study demonstrated that 4-min and 8-min breaks were both found to have a positive impact on student on-task behavior when compared to baseline. Additionally, each of the participating classrooms exhibited differences in the dosage required to produce positive effects, indicating that the appropriate dosage may vary by classroom. Furthermore, participating teachers rated student on-task behavior similarly when comparing DBR data to direct observation data gathered by external observers, supporting the idea that teachers can produce accurate ratings of student on-task behavior. Lastly, both teachers and students rated the AB intervention as acceptable, feasible, and enjoyable through the IRP-15 and KIP. While these findings are promising, additional research is required to further the evidence regarding AB dosage requirements and accuracy of teacher DBRs. [The dissertation citations contained here are published with the permission of ProQuest LLC. Further reproduction is prohibited without permission. Copies of dissertations may be obtained by Telephone (800) 1-800-521-0600. Web page: http://bibliotheek.ehb.be:2222/en-US/products/dissertations/individuals.shtml.]