Increased posterior tibial slope (PTS) is a risk factor for anterior cruciate ligament (ACL) tear and ACL reconstruction failure. Anterior closing-wedge osteotomy (ACWO) decreases the PTS and the risk of reinjury after revision ACL reconstruction. ACWO techniques include supratubercular, transtubercular, or infratubercular. However, there are limitations to the amount of slope correction an ACWO can achieve in the context of a massively abnormal slope. If the necessary slope correction is greater than 20°, a supratubercular ACWO cannot achieve the required correction without high risk of brittle fixation, a transtubercular ACWO would introduce increased morbidity of a secondary osteotomy and change the biomechanics of the patellofemoral joint resulting in significant patella alta, and an infratubercular ACWO would require a major anterior tibial metaphysodiaphyseal resection. The tibial plateau leveling osteotomy (TPLO) is an alternative curved osteotomy commonly used in canines that avoids the adverse events associated with a large ACWO. Further benefits of TPLO for massive slope correction include improved maintenance of native soft-tissue tension, avoidance of major recurvatum, and the ability to control the correct degree. We describe an open technique for a TPLO to decrease the PTS and the risk of recurrent ACL injury.