Purpose <p>Heterotopic ossification (HO) following elbow injury in children is quite rare. Multiple articles on the outcomes and complications after a lateral condyle humerus fracture in children have not mentioned heterotopic ossification as a complication. We report a short series of three cases of heterotopic ossification following surgical treatment of lateral condyle humerus fractures.</p> Methods <p>Two children with lateral condyle humerus fractures with elbow dislocation, and one child with a&#xa0;Song stage 5 lateral condyle humerus fracture, presented to us with heterotopic ossification after surgical treatment. One had bony ankylosis, while another experienced malunion of the lateral condyle fragment. One child who presented early was managed conservatively, whereas the other two presented later with mature heterotopic ossification and required excision to improve elbow motion. All children received oral indomethacin to prevent progression or recurrence.</p> Results <p>According to Hardacre’s criteria, the child treated conservatively had an excellent outcome. The children who underwent HO excision demonstrated improvements of 125⁰ and 108⁰ in elbow motion, and according to Hardacre’s criteria, both achieved good results; neither had recurrence of heterotopic ossification. Improvement in elbow motion following excision of heterotopic ossification took several years.</p> Conclusion <p>Heterotopic ossification following treatment of lateral condyle humerus fractures is rare; associated elbow dislocation may increase the risk. Awareness of this complication allows earlier diagnosis and management. Early conservative treatment with rest and indomethacin may prevent the need for surgical excision. Although excision can improve elbow motion over time, full recovery of motion may not occur. Therefore, heterotopic ossification should be recognized as a potential complication of lateral condyle humerus fracture treatment in medical textbooks.</p>