Preface The MoDeVVA workshop series brings together researchers and practitioners interested the application of validation and verification (V&V) techniques in model-driven engineering (MDE). The main goals of the workshop are to iden- tify, discuss, and elaborate mutual impacts of MDE and V&V. The 12th edition of MoDeVVA took place on the 29th of September 2015 and was co-located with MODELS15 in Ottawa, Canada. After a careful re- viewing process with many stimulating discussions, six papers were selected for presentation of the workshop. Each paper was reviewed by at least three mem- bers of the program committee. We would like to thank the members of the PC for their support in setting up an interesting program for MoDeVVA. In addition to the presentations of the papers selected by the program com- mittee, MoDeVVA 15 featured an invited presentation by Jürgen Dingel who is Associate Professor in School of Computing of Queen’s University with the ti- tle “Irrelevant or indispensable? MDE, formal methods and current computing trends”. Program Committee Mira Balaban Marius Minea Brun Barroca Ernesto Posse Frédéric Boulanger Daniel Ratiu Fabrice Bouquet Markus Scheidgen Chih-Hong Cheng Martina Seidl John Derrick Gehan Selim Michalis Famelis Jocelyn Simmonds Leen Lambers Dehla Sokenou Bruno Legeard Maria Spichkova Levi Lucio Manuel Wimmer Mercedes Merayo 1