This review examines some of the notable advances and trends that have shaped the field of computational elucidation of organic reaction mechanisms over the last 10-15 years. It highlights the types of mechanistic problems that have recently become possible to study and summarizes the methodological developments that have permitted these new advances. Case studies are taken from three representative areas of organic chemistry-asymmetric catalysis, glycosylation reactions, and single electron transfer reactions-which illustrate themes common to the broader field. These include the trend towards modelling systems that are increasingly complex (both structurally and mechanistically), the growing appreciation of the mechanistic roles of non-covalent interactions, and the increasing ability to explore dynamical features of reaction mechanisms. Some interesting new challenges that have emerged in the field are identified.