The purpose of this systematic review was to identify valid, reliable, and clinically practical measures of function/activity for children with cerebral palsy. Cochrane, MEDLINE, CINAHL, AMED, PEDro, and ScienceDirect were searched to identify relevant studies. Reference lists were hand-searched, and databases were searched specifically for outcome measures (OMs) identified. Studies were examined for bias based on published recommendations. Seven studies on 6 OMs were included, which were of moderate or good methodological quality. Most measures require further research to fully establish their psychometric properties. Only the Gross Motor Function Measure versions 88 and 66 and the Pediatric Evaluation of Disability Inventory were identified as potentially appropriate for this client group, but not all are valid for children of all ages and Gross Motor Function Classification System levels. The clinical application of these OMs is discussed in relation to capacity, capability, or performance; new developments are highlighted.