Background <p>Gender differences in mental rotation are well established. However, conflicting results were reported when gender was shown to interact with sport expertise and different task transformations in adolescents’ mental rotation.</p> Methods <p>Forty-four adolescent subjects (22 divers and 22 nonathletes) participated in the experiment. A mental body rotation task with object-based and egocentric transformation conditions was conducted, and the reaction time, accuracy, and stage performance were recorded.</p> Results <p>The results showed that in the object-based task involving cube images, the divers had shorter reaction times than did nonathletes, and the perception speed of athletic boys was faster than that of athletic girls. In the object-based task with body image, athletes’ advantage was confirmed, and the accuracy for girls was significantly greater than that for boys. No gender difference was detected in the egocentric task.</p> Conclusions <p>The mental rotation ability of adolescents was found to be significantly influenced by their mental rotation representation and motor expertise, which differed by gender.</p>