BackgroundHigh‐quality communication in pediatric and adolescent cancer is the standard of care. Yet, we lack pediatric‐specific communication measures. We designed self‐report and caregiver‐report communication measures for use in pediatric oncology settings.MethodsWe recruited adolescent and young adults (AYAs; 12–24 years) with cancer and parents of children and AYAs between 1 month post‐diagnosis and 2 months after completing treatment. Participants completed measures including 58 questions addressing eight previously characterized communication functions. For each function, we conducted factor analysis, and assessed reliability and construct validity. Based on psychometric properties, we created final long‐form (31 items) and short‐form (eight items) communication measures (PedCOM) for both self‐ and caregiver‐report.ResultsParticipants included 200 parents and 88 AYAs. The final 31‐item and eight‐item PedCOM measures for parents and AYAs demonstrated good unidimensional model fit. Each communication function (e.g., building relationships) demonstrated high reliability, coefficient alphas ranged from .83 to .93 for parents and .85 to .93 for AYAs. The overall 31‐item and eight‐item PedCOM measures also demonstrated high reliability (alphas >.9). For construct validity, PedCOM‐Parent‐31 and PedCOM‐Parent‐8 correlated positively with satisfaction with care, trust, emotional self‐management, and decisional satisfaction, and negatively with anxiety and caregiver burden. PedCOM‐AYA‐31 and PedCOM‐AYA‐8 correlated positively with satisfaction with care, trust, emotional self‐management, symptoms self‐management, and decisional satisfaction, and negatively with anxiety.DiscussionWe developed valid and reliable measures of communication functions for parents and AYAs with cancer. These measures can support organizations and stakeholder groups that are striving to improve the quality of cancer care.