Valid and efficient assessment of patient-reported outcomes remains a priority to guide pain treatment and research. PROMIS® pediatric self-report and parent-proxy measures offer feasible and rigorous evaluation of functioning in children with chronic conditions, including pain. A key challenge is determining the usefulness of multisource information from children and caregivers for understanding pain and function. Our primary aim examined child-caregiver agreement across child functioning domains. Our secondary aim examined child and caregiver factors associated with child-caregiver agreement.