This book constitutes the refereed proceedings of the 5th International Conference, ICMT 2012, held in Prague, Czech Republic, in May 2012, co-located with TOOLS 2012 Federated Conferences. The 18 full papers presented together with one invited paper were carefully revised and selected from numerous submissions. Topics addressed are such as testing, typing and verification; bidirectionality; applications and visualization; transformation languages, virtual machines; pattern matching; and transformations in modelling, reutilization.