Abstract Background Narrow-band ultraviolet (UV) phototherapy has not been used in the treatment of lichen nitidus. Aim To report two cases of generalized lichen nitidus successfully treated with narrow-band UV-B phototherapy. Methods A 7-year-old girl presented with a persisting, asymptomatic, papular eruption refractory to topical steroid for 3 months. Another 10-year-old boy presented with an asymptomatic papular eruption present for 6 months. The histopathologies of both lesions were consistent with lichen nitidus. The lesions were treated with narrow-band UV-B phototherapy. Results The lesions of the patients were almost completely cleared after the 30th and the 17th irradiation, respectively. Conclusions Narrow-band UV-B may be an effective alternative therapy for the treatment of generalized lichen nitidus unresponsive to common therapies.