Early childhood interventions aimed at reducing socioeconomic disparities hinge on parent engagement. However, sparking parents’ engagement and sustaining it throughout the course of interventions has historically been challenging. We designed program enhancements informed by the interdisciplinary field of behavioral economics to support parent engagement in Getting Ready for School, a school readiness intervention for Head Start preschoolers. The behavioral economics enhancements are hypothesized to address psychological factors that might interfere with parents’ decision-making, including attention, misestimation, and related parent biases about children's learning. Results from a randomized control design in four Head Start centers show that, compared with families that received the typical curriculum, those that received behavioral economics–enhanced strategies, such as personalized invitations, child-friendly activity planners, text-message reminders, and commitment reinforcement, had higher parent attendance and follow-through for GRS activities and spent more time with children on educational activities outside of the classroom.