Valgus tibial malalignment may be the result of bony deformity, previous lateral meniscectomy, or lateral plateau fractures. The correction of such a problem is usually addressed through a tibial osteotomy, which affects the alignment both in flexion and extension. Two surgical options are available: medial closing wedge and lateral opening wedge. When planning a varisation osteotomy, it should be considered that the normal joint line is in 3 degrees of varus. Increasing this obliquity beyond 10 to 15 degrees ends up with increased loads on the patellofemoral joint and medial subluxation of the femur on the tibia. The aim of the present study was to discuss actual indications and contraindications for a varus-producing high tibial osteotomy and describe surgical steps of both medial closing wedge and lateral opening wedge techniques. In addition, the available literature has been searched to report functional outcomes and complications.