<p>Implementation of program-wide positive behavior interventions and supports is effective for preventing undesirable outcomes in young children, while concomitantly helpful for promoting positive social-emotional, behavioral, and learning outcomes. Of utmost importance is the consistent implementation of Tier 1 practices, as they universally target all young children’s outcomes. However, early childhood educators are often inadequately trained to consistently deliver Tier 1 strategies and therefore require explicit training and support. As such, the purpose of this study was to evaluate the effectiveness of behavioral skills training for training three early education assistant teachers to implement a novel Tier 1 support, Positive Greetings at the Door, with concomitant educator and child outcomes. Results indicated that behavioral skills training resulted in immediate and sustained treatment fidelity, with medium to small effects on the assistant teachers’ frequency of reprimands. Further, improvements in children’s display of appropriate and disruptive behavior were observed in two of three classrooms. Results, implications, limitations, and future directions are discussed.</p>