Background: The Liver Imaging Reporting and Data System (LI-RADS) has standardized the evaluation of adult but not pediatric hepatocellular carcinoma (HCC). Purpose: To evaluate the performance of LI-RADS version 2018 for diagnosis of pediatric HCC. Materials and Methods: This multi-institution retrospective study evaluated all available dynamic CT and/or MRI scans of pediatric (18 years) HCC from five institutions between July 2009 and April 2019. The control group included an equal number of other enhancing hepatic lesions. Blinded to final diagnosis, three radiologists independently applied LI-RADS version 2018 criteria. The reference standard was pathologic examination or more than 1 year follow-up. Sensitivity and specificity of LI-RADS were computed using a dichotomous classification of LR-1, LR-2, or LR-3 versus LR-4, LR-5, LR-TIV (tumor in vein), or LR-M (probably or definitely malignant but not HCC-specific) for predicting hepatic malignancy in the entire cohort and in patients at risk for HCC. Results: The cohort consisted of 116 children: 58 with HCC (mean age, 12 years 6 5; 31 girls) and 58 with other enhancing hepatic masses (mean age, 12 years 6 5; 42 girls). Frequencies of major criteria in classic HCC for the three readers were as follows: nonrim arterial phase hyperenhancement, 49%–62% (19–24 of 39 patients); nonperipheral “washout,” 36%–59% (14–23 of 39 patients); and enhancing “capsule,” 28%–38% (11–15 of 39 patients). For the full cohort, the sensitivity of LR-4, LR-5, LR-TIV, or LR-M for malignancy among the three readers ranged from 85% (95% CI: 76, 94) to 88% (95% CI: 80, 96); specificity of LR-1, LR-2, or LR-3 for benignity ranged from 54% (95% CI: 40, 68) to 70% (95% CI: 57, 83). In the at-risk subgroup, sensitivity ranged from 58% (95% CI: 36, 80) to 68% (95% CI: 48, 89); specificity ranged from 56% (95% CI: 37, 74) to 63% (95% CI: 45, 81). All lesions categorized as LR-TIV (n = 10–13) were HCCs. Conclusion: Liver Imaging Reporting and Data System version 2018 had moderate sensitivity but low specificity for the diagnosis of pediatric hepatocellular carcinoma (HCC), which had low frequencies of the major criteria used for adult HCC diagnosis.