This study recruited 85 healthy children and adolescents, aged 6-18 years, from a school-based blood pressure (BP) screening study and performed office BP measurements, 24-h ambulatory blood pressure monitoring (24-h ABPM) and 24-h pulse wave analysis. Prevalence of BP phenotypes was assessed, factors that may predict hypertension (HTN) in ABPM were examined and the effect of BP phenotypes, as well as school, office, and ambulatory BP parameters on pulse wave velocity (PWV), was investigated. Forty-five (54.9%) of the children were normotensives, 8 (9.7%) were white coat hypertensives (WCH), 19 (23.2%) had masked hypertension (MH), and 10 (12.2%) had sustained HTN. Estimated adjusted marginal means for 24-h PWV were 4.79 m/s (95% CI 4.65-4.94) for sustained hypertensives, 4.72 m/s (95% CI 4.62-4.82) for MH, 4.38 m/s (95% CI 4.23-4.54) for WCH, and 4.33 m/s (95% CI 4.26-4.40) for normotensives (sustained hypertensives versus normotensives and WCH, p < 0.001, MH versus normotensives and WCH, p < 0.005). Neither body mass index (BMI) z-score nor school systolic BP (SBP) z-score could predict HTN by ABPM. Office SBP z-score was associated with 1.74 times increased odds ratio to have HTN in ABPM. Sustained HTN and MH were independent predictors of 24-h PWV after adjustment for age, sex, and BMI z-score. In conclusion, arterial stiffness in children and adolescents was assessed by 24-h PWV associates with mean ambulatory BP. Both school and office BP measurements could not predict HTN in ABPM or increasing PWV. HTN in ABPM was independently associated with the risk of higher PWV compared with normotensive and WCH phenotype.