Introduction: Childhood hypertension poses a significant public health challenge with longterm cardiovascular implications. Although adult studies have linked serum folate (SF) to hypertension, the association in children remains unclear, particularly during the pubertal transition. Objectives: To examine the associations between serum folate levels and hypertension in children before and after puberty . Method: Data from NHANES 2013–2020 were analyzed for children and adolescents with available blood pressure (BP) and SF measurements. Hypertension was diagnosed by the American Academy of Pediatrics guidelines (2017). Multivariable logistic regression and linear regression were conducted to estimate the associations of SF with hypertension and BP levels, with adjustment for age, gender, BMI, and homocysteine. Results: A total of 3,110 children and adolescents were included, comprising 1,575(50.6%) boys, with a mean age of 12.3±2.9 years. A total of 1,637 participants were under the age of 13. The prevalence of hypertension was 6.2% in participants under 13, and 3.1% in those over 13. The median SF level was 48.7 (IQR: 36.5–63.0) nmol/L, with higher levels in participants under 13 than over13 (P