Background: Genu valgum is a common coronal plane malalignment in children that often resolves spontaneously during early growth. However, in cases where the deformity persists beyond physiologic limits intervention becomes necessary. A non-locking extraperiosteal plate and two screws make up the 8-plate tension-band system, which functions as a tension band. It offers a minimally invasive, flexible, and reversible alternative that reduces the risk of physeal damage due to its extraperiosteal design. Assessing the degree of correction achieved with tension band plating in patients with idiopathic genu valgum and determining the intermediate to long-term outcomes were the goals of this study. Methods: This prospective study was conducted on eleven patients with 190 valgus deformities of the knee treated with medial hemiepiphysiodesis using one tension band plate. The tibiofemoral angle (TFA) and the anatomic lateral distal femoral angle (aLDFA) were assessed on anteroposterior (AP) radiographs of the lower extremity during follow up visits. The average time of follow-up from index surgery was 5 to 7 years. Results: The mean correction time was 11.2 months. The TFA was corrected from a mean 12.2o preoperatively to 4.6o postoperatively. The aLDFA was also corrected from a mean of 78.7o preoperative to a mean 83.9o postoperative. There were no instrumentation failures. Conclusion: Effective and predictable correction of idiopathic genu valgum before skeletal maturity can be obtained by distal femoral hemiepiphysiodesis using tension band plating.