Persons with type 1 diabetes are at increased risk of developing vascular disease. Adiponectin concentrations may play an intermediate role in this process. We sought to determine whether adiponectin is correlated with vascular stiffness in adolescents with type 1 diabetes. Plasma adiponectin, pulse wave velocity (PWV), augmentation index (AIx-75), and brachial distensibility (BrachD) were collected in 225 adolescents. Outcomes were evaluated by sex, and regression models were used to determine whether adiponectin was an independent determinant of arterial stiffness. Males had lower adiponectin levels and stiffer vessels (lower BrachD, p < 0.01) than females. Unadjusted correlations revealed that adiponectin was correlated with BrachD (p < 0.01) but not PWV and AIx-75. After adjustment, adiponectin was not a significant predictor of BrachD. The most consistent predictors of increased stiffness were age, male sex, blood pressure, obesity, and total cholesterol (p < 0.05). Adiponectin's contributions to arterial stiffness appear to be masked by other cardiovascular risk factors in persons with type 1 diabetes.