Background: Femoral neck fracture nonunion is a frequent and challenging complication, with several surgical options. Objectives: The present study reported the outcome of valgus osteotomy for treating femoral neck nonunion in patients aged <65 years. Methods: This case series research included young patients who underwent valgus osteotomy for treating femoral neck nonunion or device failure of the index surgery. The fixation of the osteotomy site was performed using either a dynamic hip screw or a fixed angle blade. The union of the neck and osteotomy site (subtrochanteric region) was evaluated by monitoring callus formation in the postoperative radiographs. Limb length discrepancy, Pauwels’ angle, and the neck-shaft angle were evaluated before the surgery and at the last follow-up. Postoperative complications were extracted from the explored patients’ profiles. Results: Twenty patients with a Mean±SD age of 27.2±10.8 years were examined in this study. The Mean±SD follow-up time of the patients was 6.1±3.9 years. The femoral neck was united in 18 patients in a Mean±SD period of 5.1±2.3 months. The Mean±SD limb length discrepancy was measured as 1.3±0.8 cm before and 0.5±0.7 cm after the osteotomy. The Mean±SD Pauwels’ angle was calculated as 65.5±16.9º before and 32.4±16.2º after the osteotomy. The Mean±SD neck-shaft angle was computed to be 121.9±22.8º before and 144.5±17.7º after the osteotomy. Revision surgery was performed for 6 (30%) patients. This measure included device removal in 4 and total hip arthroplasty in 2 patient. Conclusion: Valgus osteotomy is a safe and efficient technique for managing femoral neck nonunion. Therefore, this approach is suggested as a good alternative for total hip arthroplasty, particularly in young and active patients.