Laugier-Hunziker syndrome (LHS) is a rare, idiopathic pigmentary disorder especially affecting the lips and oral mucosa. At present, no more than 200 cases of patients diagnosed with LHS syndrome have been described worldwide. To date, three patients under the age of 20 have been described, including the youngest patient who is a 12-year-old child. The exact etiology of LHS still remains uncertain, as there is no evidence of systemic symptoms or increased cancer risk. The final diagnosis of LHS is possible after the exclusion of other, more serious diseases involving skin-mucosal hyperpigmentation, mainly Peutz-Jeghers syndrome (PJS) and Addison's disease (AD). Herein, we present a 16-year-old patient who has been diagnosed with oral hyperpigmentation since the age of 13. We reviewed the clinical and histological findings. In addition, we discussed the differential diagnosis of mucocutaneous hyperpigmentation.