Masked hypertension (MH) and white-coat hypertension (WCH) are associated with organ damage. In the present study, we examined the correlation between the magnitude of white-coat effect (WCE) or reverse WCE (RWCE) and 24-h pulse pressure (PP), an indicator of target organ damage and arterial stiffness, in children and young adults. We also examined the relationship of WCE or RWCE and blood pressure (BP) variability, another predictor of clinical outcomes. One hundred and ninety-eight subjects were studied. According to the office BP and ambulatory BP, they were divided into normotension, WCH, MH, and hypertension. The magnitude of WCE or RWCE, along with male gender and 24-h systolic BP, was the determinant of 24-h PP. In subjects with 24-h PP ≥ 61 mmHg, the magnitude of WCE or RWCE, age, male ratio, height, weight, BMI, the percentage of secondary hypertension, that of MH, office systolic BP, and 24-h systolic BP were significantly greater. There was a progressive increase in 24-h PP from normotension, WCH, MH, to hypertension. BP variability in subjects with MH was numerically highest in both systolic and diastolic. Diastolic BP variability of WCH, MH, and hypertension was significantly higher than that of normotension. Finally, the magnitude of WCE or RWCE in systolic showed a significant correlation with systolic BP variability. In conclusion, the magnitude of WCE or RWCE correlates with 24-h PP and systolic BP variability, which may suggest increased arterial stiffness in WCH and MH.