Hypervitaminosis D is an uncommon cause of hypercalcaemia and is usually due to excessive oral supplementation. We report a case of an elderly woman who presented with symptomatic severe hypercalcaemia secondary to hypervitaminosis D that did not respond well to conventional therapy. Administration of single dose denosumab resulted in rapid improvement of hypercalcaemia which remained stable at outpatient follow-up with a decline in vitamin D level as well. There is little evidence for use of denosumab in hypercalcaemia not due to malignancy, so this case highlights its safe and effective use in this setting, which may be useful when other treatment is contraindicated.