Children with cerebral palsy (CP) and other medical complexity comprise an outsized proportion of health care use. In this review, we describe the current science of assessment of nutritional status for children with CP, outline a systematic approach to assessing their nutritional status, delineate ramifications of malnutrition on hospitalization-associated outcomes, and identify knowledge gaps and means of addressing those gaps using quality improvement and clinical research tools. Methods to accurately assess body composition and adiposity in this population by using skinfolds, age, sex, and activity level are available but are not widely used. There are limitations in our current method of estimating energy needs in children with CP, who are at higher risk of both obesity and micronutrient deficiencies. There is some evidence of an association between malnutrition, defined as either underweight or obesity, and hospitalization-associated outcomes in children generally, although we lack specific data for CP. The gaps in our current understanding of optimal nutritional status and between current science and practice need to be addressed to improve health outcomes for this vulnerable patient population.