This article presents a survey of recent applications of advanced computer modelling techniques in the study of ion transport and defect properties of ABO3 perovskite-structured oxides. The principal methodologies are outlined which include techniques based upon both interatomic potentials (static lattice, molecular dynamics) and quantum mechanical methods. The scope of contemporary applications of computer modelling of perovskite oxides (such as LaBO3 and AZrO3) is illustrated by accounts of recent work on oxygen ion transport and defect association, on cation migration, and, finally, on proton incorporation and diffusion.