This review highlights recent advances in X-ray microcomputed tomography (microCT) as applied to materials, specifically advances made since the first materials microCT review appeared in International Materials Reviews. Improvements in instrumentation are covered, and one focus is microCT using phase (as opposed to absorption) contrast. Instead of grouping studies by disciplines, the reviewed reports are organised by type of application, specifically the study of the spatial distribution of phases, of cellular solids (including static and temporally evolving structures, fibrous network solids, mineralised tissues and biomedical applications), of channel structures, of deformation, fatigue and fracture, of processing and of corrosion and environmental interactions. Metrology applications are covered briefly, and several applications where microCT is combined with position resolved X-ray scattering are described in more detail. The accuracy of microCT reconstructions is discussed before data handling challenges are outlined. The review closes with speculations on the future directions of materials microCT.