Juvenile xanthogranuloma (JXG) is a histiocytic proliferative tumor that predominantly affects infants and young children. It is classified as a benign disease that comprises the majority of non-Langerhans cell histiocytes and is characterized by reddish-brown or yellow papules and nodules commonly found on the face and trunk. Although JXG presents with distinct clinical features, an exceedingly uncommon subset of JXG includes lesions that surpass 20 mm in diameter, referred to as giant JXG, which can occasionally be misdiagnosed as other tumors. Herein, we report a rare case of a giant JXG in a 1-month-old Korean boy, highlighting the significance of accurate diagnoses. Additionally, we provide a comprehensive literature review to enhance our understanding of this rare variant.