Background: Childhood obesity is associated with hypertension (HT), arterial stiffness, and increased cardiovascular risk. Urocortin 2 (UCN2), a member of the corticotropin-releasing factor family, exerts vasodilatory and cardioprotective effects; however, its role in obesity-related vascular dysfunction in children remains unclear. We aimed to investigate the relationship between circulating UCN2 levels, HT, and arterial stiffness parameters in children with obesity. Methods: This prospective, single-center, cross-sectional case-control study included 154 children aged 10–18 years: 95 with obesity and 59 healthy controls. Anthropometric measurements, serum UCN2 concentrations, and metabolic parameters were assessed. Brachial-based oscillometric pulse wave analysis was performed to obtain estimated pulse wave velocity (PWV), augmentation index corrected for a heart rate of 75 beats/min (AIx@75), central systolic blood pressure (cSBP), and other hemodynamic parameters. Multivariable linear regression analyses were used to identify independent predictors of UCN2 and arterial stiffness. Results: Children with obesity had significantly higher PWV, cSBP, pulse pressure, cardiac output, and HT prevalence compared with controls (all p < 0.001). Although UCN2 levels tended to be lower in children with obesity, the difference was not statistically significant (p = 0.196). In children with obesity, UCN2 was negatively correlated with body mass index (r = −0.31, p = 0.003) and pulse pressure (r = −0.22, p = 0.031), and log-transformed UCN2 levels were negatively correlated with PWV (r = −0.22, p = 0.034). The independent negative association between UCN2 concentrations and PWV indicates an inverse relationship with arterial stiffness in childhood obesity. However, further longitudinal and mechanistic studies are required to determine whether this association reflects a underlying physiological involvement or therapeutic target. Conclusions: Childhood obesity is associated with adverse vascular alterations and increased arterial stiffness. The independent inverse association observed between UCN2 and PWV highlights a biological link with vascular stiffness in childhood obesity. However, whether UCN2 possesses biomarker utility or therapeutic relevance remains speculative and warrants evaluation in prospective longitudinal and clinical studies.