The MPM workshop series brings together researchers and practitioners interested in using explicit and heterogeneous models throughout the design of a system. The 8th edition will take place on 30 September 2014 and will be co-located with MODELS'14 in Valencia, Spain. Out of the 9 papers submitted and reviewed by at least four members of the program committee, 8 were selected for oral presentation. The average reviewer score for the accepted papers was +0:48 on a scale of 3 to +3. In addition to the presentation of the selected papers from the technical program, MPM'14 will feature an invited presentation by Akos Ledeczi on WebGME. This volume contains versions of the selected papers that the authors had the opportunity to enhance by taking into account reviewers' comments.