The anterior cruciate ligament (ACL) functions to provide translational and rotatory stability of the knee. ACL injury is diagnosed through a combination of history, physical examination, and imaging, and can be treated successfully with both operative and nonoperative approaches. However, persistent knee instability following a trial of nonoperative management, or the desire to return to demanding (often pivoting) sports and/or minimize secondary damage to other knee structures, supports surgical intervention. Anatomic ACL reconstruction is the standard-of-care, but surgical timing, graft size, and graft source (including autografts and allografts) should be individualized for each patient. Concomitant meniscal tears should be repaired whenever possible. Consideration for repair or reconstruction of injured collateral ligaments and/or anterolateral complex is decided on an individual basis. Rehabilitation, whether pursued as part of nonoperative management or in the pre- and postoperative course, should progressively increase movement intensity and complexity. Return-to-sport (RTS) testing can facilitate the determination of when full activity may be resumed. Evidence supports a minimum of 9 months from surgery to RTS to reduce the risk of re-tear in patients.