In clinical practice, it is observed that the hamstring tendon graft, despite being first choice in knee ligament reconstruction, may not present adequate size. Therefore, it becomes necessary to search for other graft alternatives. In this context, the peroneus longus tendon arises as an option to replace or complement other grafts. The surgeon can opt to use the tendon in its totality or only its anterior half, presenting adequate length, diameter, and biomechanics, without major repercussions for the donor site. In this study, we report a case of an athlete in which the autologous hamstring tendon graft did not present the adequate diameter for anterior cruciate ligament reconstruction. It was, then, necessary to use the anterior half of the peroneus longus tendon.