ObjectivePatient education is central to Enhanced Recovery After Surgery protocols, but child‐focused materials are lacking. We developed and piloted a mobile application to support accessible, interactive patient and caregiver education about pediatric tonsillectomy.MethodsThirty children ages 5–12 who were preparing for tonsillectomy, their caregivers, and six attending otolaryngologists participated in a user‐testing trial of a web‐based prototype. The trial measured feasibility, fidelity, and patient‐centered outcomes. Patients and caregivers rated usability/likeability on the mHealth App Usability Questionnaire. Otolaryngologists rated quality on the Mobile App Rating Scale. The full mobile application, “Ready for Tonsillectomy,” was then developed for iOS and Android.ResultsEnrollment was 88.2%, retention was 90.0%, and use was 96.3%. Mean (SD) patient ratings for usability/likeability were 6.3 (1.1) out of 7; caregiver ratings were 6.5 (1.1). In common themes from open‐ended feedback, patients described the application as helpful and appealing, and caregivers described it as informative, easy to understand, calming, and easy to use. Among caregivers who used the application during recovery, 92.3% reported that it helped them manage their child's pain. Providers would recommend the application to many or all of their patients (mean [SD]: 4.7 [0.5] out of 5). Mean provider ratings for domains of engagement, functionality, aesthetics, information quality, subjective quality, and app‐specific value ranged from 4.1 to 4.8 out of 5.ConclusionFeasibility and fidelity were high. Families and otolaryngologists endorsed the resource as an engaging, informative tool that supports positive coping. Our mobile application offers a patient‐centered solution readily scalable to other surgeries.Level of EvidenceN/A Laryngoscope, 2023