Nannizziopsis guarroi infection in lizards presents therapeutic challenges, with reports of poor clinical outcomes, including antifungal toxicity, incomplete clearance of infection, and recrudescence of infection being common. The case presented here describes the successful treatment of an N. guarroi infection using systemic terbinafine and environmental disinfection in a captive-bred central bearded dragon (Pogona vitticeps). The lizard presented with darkly colored cutaneous lesions, and mycologic culture samples were identified as N. guarroi using matrix-assisted laser desorption/ionization–time of flight. Based upon the lack of clinical resolution of cutaneous lesions, weight loss, and reduced appetite, initial treatment with voriconazole was discontinued. Terbinafine was prescribed, and weekly environmental disinfection with sodium hypochlorite was initiated until cutaneous clearance of the fungus was confirmed by negative culture, histopathology, and N. guarroi quantitative polymerase chain reaction from cutaneous swab. Terbinafine treatment was discontinued after 80 days. There were no clinical signs of toxicity associated with the prolonged treatment, and the lizard has not developed any cutaneous lesions or illness in more than 2 yr of clinical follow-up. Although the ideal treatment of N. guarroi is still being investigated, this case demonstrates a promising and safe treatment option for an increasingly common and devastating disease.