This study aimed to address this gap by examining low and high parent engagement with the Healthy Me, Healthy We campaign to identify barriers and facilitators of parent engagement with the intervention. Method. This comparative case study used an explanatory sequential mixed-methods approach. We created center-level parent engagement scores using process evaluation data from the effectiveness trial of Healthy Me, Healthy We. Recruitment focused on centers with the five lowest and five highest scores. Twenty-eight adults (7 directors, 9 teachers, 12 parents) from seven centers (3 low engagement, 4 high engagement) completed semistructured interviews and the Family and Provider/Teacher Relationship Quality measure. Analytic approaches included descriptive statistical analyses for surveys and a framework-informed thematic analysis for interviews. (author abstract)