The posterolateral corner (PLC) of the knee consists of three major structures: the fibular collateral ligament (FCL); popliteus tendon (PLT); and popliteofibular ligament (PFL). The structures of the PLC play a primary role in preventing varus rotation and excessive external rotation of the knee. Injuries to the PLC commonly occur in the presence of injuries to other major structures of the knee, including the cruciate ligaments and meniscus. The presentation of PLC injuries can be overshadowed by concomitant injuries and often go underdiagnosed. PLC injuries can be reliably diagnosed with thorough physical examination and imaging, including varus stress radiographs. Nonoperative treatment has been demonstrated to be effective for grade I or grade II PLC injuries, although surgical treatment is required to restore stability to grade III PLC injured knees. Anatomic PLC reconstruction has developed into the standard of care for grade III PLC injuries and has resulted in improved objective and subjective patient outcomes.