The goal of the International Classification of Functioning is to standardize the classification of health and function of children around the world. To facilitate the application of this classification, International Classification of Functioning–based tools like the “Core Sets” are being developed. We conducted an international survey of professional experts to identify the most relevant areas of functioning in children with cerebral palsy. The questionnaire covered each component of the classification. In total, 193 professionals completed the survey (response rate 78%). Overall, 9706 answers were linked to the classification (pediatric version) by 2 professionals. From the experts’ perspective, movement-related areas and social participation are the most relevant areas of functioning. Experts suggest a more comprehensive profile of functioning in particular in areas of personal capacity and social participation. The results of this survey will inform the development of the International Classification of Functioning Core Sets for children with cerebral palsy.