Background: Kirschner wires (K-wires) are commonly used to treat displaced lateral humeral condyle fracture in children. However, K-wire fixation alone is insufficient for early elbow range of motion (ROM) exercises. Fixation combined with tension band wiring (TBW) converts distraction forces into compression forces, which provides more rigid fixation than K-wire fixation alone. Here, we retrospectively evaluated clinical outcomes of patients with displaced lateral humeral condyle fracture treated with TBW or K-wires only. Methods: We identified children with lateral condyle fractures who had undergone surgery during the period from April 2000 through March 2014. Nineteen patients were classified into 2 groups according to treatment: 10 were allocated to the TBW group (TBW and K-wires) and 9 to the K-wires group. The mean interval from injury to surgery was 5.1 days in both groups. Fractures were classified by using the Jacob's and Milch's classifications. In addition, we collected and analyzed data on postoperative complications, radiological and clinical evaluations, ROM, and Flynn's criteria. Results: Mean duration of follow-up was 14.4 months in the TBW group and 5.9 months in the K-wires group. Mean bone union time was 38.6 days and 49.8 days, respectively. Mean duration of cast/splint use was significantly longer for K-wires patients (49.8 days) than for TBW patients (35.8 days). Range of flexion at the final follow-up was significantly lower in the K-wires group. Conclusions: TBW fixation appears to be the optimal treatment for displaced lateral humeral condyle fracture in children, as it facilitates early active range of motion exercises.