Multitiered support for professional development (MTS-PD) is emerging as a research-supported, three-tiered framework to support teachers' classroom management skills through targeted training and ongoing coaching. In this study, we applied MTS-PD to increase elementary general education teachers' treatment fidelity of a targeted behavioral support (i.e., self-monitoring) and examined whether increases in treatment fidelity were accompanied by increases in on-task behavior for three focal students who were identified as at-risk of being identified for having an emotional/behavior disorder. Results, which were evaluated in the context of a multiple-probe, single-case research design, indicated that MTS-PD increased teachers' treatment fidelity. However, outcomes were inconsistent with regard to increases in focal students' on-task behavior and decreases in rate of disruptive behavior as a result of increases in treatment fidelity. Results of this study demonstrate that MTS-PD can support teacher implementation of targeted behavioral supports. Practical and research implications are discussed.