Eosinophilic granuloma (EG) is a rare histiocytic disorder resulting from clonal proliferation of Langerhans cells. Eosinophilic granuloma, the most benign of the three entities of Langerhans cell histiocytosis, may be multiple or solitary. This lesion can affect any bones but commonly involves the mandible when the jaws are affected. It is difficult to make a correct diagnosis on it without proof of a pathological diagnosis, which correlates with the diverse clinical and radiographic presentations of EG in the jaws. This report describes a case of unifocal EG of the mandible occurring in a 6-year-old boy whose initial presentation led to confusion of any solitary bony lesion. A final diagnosis of EG was established after histopathological examination of the biopsy specimen.