Injury to the anterior cruciate ligament (ACL) can result in recurrent instability, impairment, and progressive joint damage in athletes who return to high-risk sports activities. ACL reconstruction often is indicated. With refinement of surgical techniques and accelerated rehabilitation, the number of complications following ACL reconstruction has greatly decreased since the 1980s. Nevertheless, ACL reconstruction remains a complex procedure with multiple steps and many possible complications. Understanding the incidence and etiology of the more common complications associated with ACL reconstruction during the preoperative and postoperative periods is important to manage (if not avoid) the risk of these complications.