This clinical practice guideline (CPG) provides clinicians with recommendations regarding chemotherapy emetogenicity classification in pediatric oncology patients. This information is critically important for the appropriate selection of antiemetic prophylaxis. Recommendations are based on a systematic review limited to pediatric patients and a framework for classification when antiemetic prophylaxis is provided. Findings of 87 publications informed the emetogenicity classification of 49 single-agent and 13 combination-agent regimens. Information required for the classification of many chemotherapies commonly administered to pediatric patients is lacking. In the absence of pediatric data, consultation of methodologically sound CPGs aimed at adult oncology patients may be appropriate.