Purpose <p>Medial compartment knee osteoarthritis is a common disease that causes functional limitations due to the overload in the weight-bearing portion of the medial compartment of the knee joint. While total knee arthroplasty is an effective treatment option in advanced stages, less invasive approaches are needed in early and mid-stage disease. Proximal fibular osteotomy (PFO) has emerged in recent years as a simple, low-cost, and implant-free alternative surgical method for medial compartment knee osteoarthritis. The aim of this review is to critically evaluate the mechanisms of action, clinical and radiological outcomes, complications, and current level of evidence for PFO.</p> Methods <p>This narrative review summarizes the current literature on proximal fibular osteotomy for medial compartment knee osteoarthritis, focusing on proposed mechanisms, clinical and radiological outcomes, complications, and limitations of existing evidence.</p> Results <p>Studies in the literature show that PFO reduces knee pain, improves functional scores, and can provide medial joint space widening. Most reported complications are transient peroneal nerve damage, and the rate of permanent damage is low. However, there is no single theory explaining the mechanism of action of PFO; rebalancing of load distribution, reduction of varus deformity, and biomechanical changes all play a role. Most current studies are retrospective, have a limited number of patients, and short-to-medium follow-up periods, and the results are heterogeneous.</p> Conclusion <p>PFO may represent a potentially useful treatment option for selected patients with medial compartment knee osteoarthritis. Patient selection, optimal osteotomy level, long-term efficacy, and comparative superiority over other surgical methods are not yet clear. Larger, prospective, and long-term studies are needed.</p>