A 3-year-old, female Gray's monitor (Varanus olivaceus) was evaluated for acute obtundation, muscle rigidity and ptyalism. Clinical signs worsened over 24 hours and were compatible with scorpion envenomation. Endoscopy confirmed the presence of an Arizona bark scorpion (Centuroides sculpturatus) within the stomach and scorpion antivenom, Alacramyn (Instituto Biolon, Mexico), was administered intravenously. The patient was hospitalised and required supportive care for 2 weeks. Clinical signs and mobility markedly improved by 6 weeks and the monitor appeared normal at 8 weeks. Significant disease secondary to scorpion envenomation is uncommonly reported in animals. This case highlights the clinical presentation and treatment approach in a reptile, with a successful outcome.