MicroCT (Micro–computed tomography) data of the left lower jaw of the Carboniferous stem tetrapod Crassigyrinus scoticus (GSE 4722), which was scanned in three parts (the specimen is preserved in three parts). The specimen was scanned at the Natural History Museum’s Imaging and Analysis Centre on a Nikon XH 225 microCT scanner in February 2013 and reconstructed as DICOM image stacks. All three parts were scanned at 210 kV and 240 mA. Part 1 represents the anterior part of the jaw and the scan produced 1995 transverse slices with a resolution of 0.1271 mm/voxel. Part 2 represents the middle part of the jaw and the scan produced 1995 transverse slices with a resolution of 0.1099 mm/voxel. Part 3 represents the posterior part of the jaw and the scan produced 1687 transverse slices with a resolution of 0.1099 mm/voxel. It was collected by Laura Porro and Jennifer Clack for anatomical description of the specimen and further biomechanical analyses.