Chioninia coctei (formerly Macroscincus coctei) was one of the largest skinks to have ever lived. In the course of a little more than 100 years it was discovered, ignored, described, forgotten, rediscovered, became a popular zoo and terrarium animal, and became extinct in the wild, with the last living captives straggling into the early 20th century. Despite numerous anatomical studies, no previous researchers have characterised the skeleton of this giant skink in detail. We prepared high-resolution x-ray CT-scans of an adult female specimen in the collection of the Royal Belgian Institute of Natural Sciences in Brussels and conducted a bone-by-bone analysis of the skull and postcranial skeleton. Although similar to congeners and other mabuyine skinks, the skull is particularly robust and the circumorbital elements, especially the jugal, are massive, as is the mandible, which has a very prominent coronoid bone. In the basicranium, the basipterygoid processes are robust and the paroccipital processes are broad. The dentition, as has long been known, is distinctively multicuspid. The axial and appendicular skeleton is consistent with this lizard's presumed rupicolous habits. The specimen we examined was likely part of the large collection of living C. coctei assembled in Torino by Mario Peracca in the late 19th century. Like several other modern studies of this species, our osteological investigation was dependent on museum collections, which allow us to extract data from now extinct taxa. Citation: Bauer, A.M., Fenner, K., Daza, J.D., Pauwels, O.S.G. & Brecko, J. 2023. Bones of a giant: the osteology of the extinct Cape Verdean skink Chioninia coctei. P. 32 in: Programme & Abstracts. 22nd European Congress of Herpetology, University of Wolverhampton, 4-8 September, 2023