Preface The Doctoral Symposium of the 18th ACM/IEEE International Conference on Model Driven Engineering Languages and Systems (MoDELS) took place in Ottawa, Canada on September 29, 2015. It received 13 submissions, all of which were reviewed by at least three members of the program committee. This committee included senior members of the MoDELS community as well as authors of papers presented in the MoDELS Doctoral Symposium in 2014. Out of the 13 submissions, 9 were accepted and presented during the symposium. Each author was allocated a 20-minute slot to present the current status of their research project, followed by 20 minutes of discussion. The program committee included the following members: ● Istvan Rath, Budapest University of Technology and Economics, Hungary ● Jeff Gray, University of Alabama, USA ● Eugene Syriani, University of Montreal, Canada ● Shiva Nejati, University of Luxembourg, Luxembourg ● Juan De Lara, Universidad Autonoma de Madrid, Spain ● Sahar Kokaly, McMaster University, Canada ● David Méndez-Acuña, Universidad de los Andes, Colombia ● Reiner Jung, Kiel University, Germany ● Adolfo Sanchez-Barbudo Herrera, University of York, UK ● Jorge Sedeño, University of Seville, Spain ● Simon Van Mierlo, University of Antwerp ● Luis Silvestre, University of Chile, Chile ● Davide Arcelli, Università de L'Aquila, Italy The day concluded with an expert panel, moderated by Dimitris Kolovos, which answered questions submitted by the students. Members of the panel were: ● Jeff Gray, University of Alabama, USA ● Eugene Syriani, University of Montreal, Canada ● Silvia Abrahão, Universidad Politecnica de Valencia, Spain We thank the authors for their contributions and members of the Program Committee and panelists for their insightful feedback. Doctoral Symposium Chairs, Marsha Chechik Dimitris Kolovos University of Toronto, Canada University of York, UK November 11, 2015