This study aimed to compare the sensitivity and specificity of the European League Against Rheumatism/American College of Rheumatology-2019 (EULAR/ACR-2019) classification criteria with prior classification schemes for patients with childhood-onset systemic lupus erythematosus (cSLE). This single-center retrospective study examined 53 patients with cSLE and 53 patients having antinuclear antibody (ANA) titers ≥ 1:80 but not cSLE as controls. Sensitivity and specificity were calculated for the EULAR/ACR-2019 criteria, original criteria reported earlier in 2019, the ACR-1997 criteria, and the Systemic Lupus International Collaborating Clinics-2012 (SLICC-2012) criteria. The frequency of positivity in the cSLE group for each item of the EULAR/ACR-2019, ACR-1997, and SLICC-2012 criteria was determined. Characteristics of the misclassified patients were also investigated. All patients with cSLE had ANA titers ≥ 1:80. The non-SLE diagnoses included juvenile idiopathic inflammatory myopathies, primary Sjögren's syndrome (pSS), juvenile idiopathic arthritis, systemic sclerosis, mixed connective tissue disease (MCTD), and others. Sensitivities of the EULAR/ACR-2019 criteria, the original criteria, the ACR-1997 criteria, and the SLICC-2012 criteria were 100%, 100%, 86.8%, and 100%, respectively; the specificities were 84.9%, 92.5%, 98.1%, and 88.7%, respectively. In the cSLE group, the items of the SLE-specific antibody (100%), complement (98.1%), hematological (94.3%), and renal (84.9%) domains were frequently observed in the EULAR/ACR-2019 criteria. The EULAR/ACR-2019 criteria misclassified patient controls more frequently, especially those with MCTD or pSS, as having SLE than the previous criteria. The EULAR/ACR-2019 criteria for cSLE had high sensitivity but low specificity; the weighted scoring of the original criteria reported earlier in 2019 may confer higher specificity and be more appropriate for the classification of SLE in a pediatric population. Key Points • The EULAR/ACR-2019 criteria for cSLE had high sensitivity but low specificity. • The EULAR/ACR-2019 criteria more frequently misclassified non-SLE patients who did not have SLE, especially those with MCTD or pSS, as having SLE than the previous criteria in patients with childhood onset. • The weighted scoring of the original criteria reported earlier in 2019 may confer higher specificity and be a more appropriate classification of SLE for a pediatric population.