Purpose To investigate the associations of peak oxygen uptake (V̇ O2peak) and V̇ O2 at ventilatory threshold (V̇ O2 at VT) with arterial stiffness in adolescents. Methods The participants were 55 adolescents (36 girls, 19 boys) aged 16–19 years. Aortic pulse wave velocity (PWVao) and augmentation index (AIx%) were measured by non-invasive oscillometric device from right brachial artery level. V̇ O2peak was directly measured during a maximal ramp test on a cycle ergometer. V̇ O2 at VT was determined using the equivalents for ventilation (V̇ E/V̇ CO2 and V̇ E/V̇ O2). V̇ O2peak and V̇ O2 at VT were normalised for body mass (BM) and lean mass (LM). Data were analysed using linear regression analyses and analysis of covariance adjusted for age and sex. Results V̇ O2peak normalised for BM (β=−0.445, 95% CI −0.783 to −0.107) and V̇ O2peak normalised for LM (β=−0.386, 95% CI −0.667 to −0.106) were inversely associated with PWVao. A higher V̇ O2 at VT normalised for BM (β=−0.366, 95% CI −0.646 to −0.087) and LM (β=−0.321, 95% CI −0.578 to −0.064) was associated with lower PWVao. Adolescents in the lowest third of V̇ O2peak by LM (6.6 vs. 6.1 m/s, Cohen’s d=0.33) and V̇ O2 at VT by LM (6.6 vs. 6.0 m/s, Cohen’s d=0.33) had a higher PWVao than those in the highest third of V̇ O2peak or V̇ O2 at VT by LM. Conclusions Higher V̇ O2peak and V̇ O2 at VT by BM and LM were related to lower arterial stiffness in adolescents. Normalising V̇ O2peak and V̇ O2 at VT for LM would provide the most appropriate measure of cardiorespiratory fitness in relation to arterial stiffness.