Communication is essential to providing family-centered care in pediatric oncology. Previously, we developed a functional model of communication between parents and clinicians. Prior research has not examined the domains and purposes of communication between children and clinicians. We explored parental perspectives to begin understanding this communication. Secondary analysis of semi-structured interviews with 80 parents of children with cancer across 3 academic medical centers during treatment, survivorship, or bereavement. We employed semantic content analysis, using the functional model of parental communication as an a priori framework. We identified 6 distinct functions of communication in child-clinician interactions: building relationships, promoting patient engagement, addressing emotions, exchanging information, managing uncertainty, and fostering hope. These communication functions were identified by parents of older (> 13 years old) and younger (< 12 years old) children, although the specific manifestations sometimes differed by age. Notably, age was not always an indicator of the child's communication needs. For example, some parents noted older children who did not want to discuss difficult topics, whereas other parent described younger children who wanted to know every detail. Two functions from the previous parental model of communication were absent from this analysis: supporting family self-management and making decisions. Interviews with 80 parents provided evidence for 6 distinct functions of communication between children and clinicians. These functions apply to older and younger children, although specific manifestations might vary by age. This functional model provides a framework to guide clinicians' communication efforts and future communication research.