Teachers appear to feel challenged by children’s off-task behavior in the classroom. Children’s off-task behavior can result in reduced academic engagement, increased teaching stress, and strained teacher-child relationships. The purpose of this study was to investigate the impact of kinder training on young children’s on-task behavior in the classroom. This study utilized an experimental single-case methodology and a multiple baseline across subjects design. Three elementary school teachers conducted weekly individual play sessions with students they identified as frequently exhibiting off-task behavior. The three children ranged in age from five to six years: two males and one female, two Caucasian non-Hispanic and one biracial. Two trained observers repeatedly assessed the child participants’ on-task behavior using the Direct Observation Form throughout the baseline and intervention phases. The findings provide support for kinder training as an effective play-based professional development-training model that can improve children’s on-task behavior. Results demonstrated that all child participants showed improvement in on-task classroom behavior. Visual analysis revealed that all child participants demonstrated a positive change in on-task behavior during the intervention phase. All teacher participants reported observing improvement in the child participants’ on-task behavior and teacher-child relationships. Teachers’ post-intervention reports supported the notion of reciprocal interactions among teacher-child relationships, understanding of children’s lifestyle and goals of misbehavior, and children’s on-task behavior.