PURPOSE: To evaluate Humphrey Visual Field (HVF) test reliability and its associated risk factors in children with glaucoma or glaucoma suspect. DESIGN: Retrospective cohort study. METHODS: None. SETTING: Single-center childhood glaucoma clinic. PATIENT POPULATION: One hundred thirty-six patients aged ≤18 years with glaucoma/glaucoma suspect, and least 1 completed 24 to 2 HVF test between 2018 and 2023. OBSERVATION PROCEDURE: Demographic and clinical characteristics including age, primary language, visual acuity (VA), and glaucoma diagnosis were extracted from electronic health records. MAIN OUTCOME MEASURES: HVF 24 to 2 testing metrics, including FP, FN, and FL. Tests were defined as reliable using manufacturer guidelines of ≤33% FP, ≤33% FN, and ≤20% FL. For each patient, a reliability score was calculated as the percentage of reliable tests among all tests completed. A multivariable logistic regression model was used to determine factors associated with test-level reliability (yes/no). A multivariable linear regression model was used to determine factors associated with patient-level reliability score. RESULTS: Among 634 HVFs from 136 patients (Mean ± SD age at first test 12.0 ± 3.2 years, 47.8% female), 51.3% were reliable. Older age, better baseline VA, and English as primary language were associated with greater odds of test-level reliability (P < .04). Mean ± SD patient-level reliability score was 51.7 ± 38.1%. Older age at first clinic visit, better baseline VA, and English as primary language were associated with higher reliability scores (all P < .02), and number of prior VF tests was not (P = .56). CONCLUSIONS: Younger age, worse visual acuity, and non-English as primary language were associated with decreased reliability and should be considered when interpreting VF testing in children. A significant learning effect was not observed with repeated testing.