The European Conference on Software Architecture (ECSA) is the premier European software architecture conference, providing researchers, practitioners and educators with a platform to present and discuss the most recent, innovative and significant findings and experiences in the field of software architecture research and practice. The 12th European Conference on Software Architecture (ECSA 2018) will be held on 24 – 28 September 2018 at Madrid, Spain, and is hosted by the Universidad Politécnica de Madrid (UPM).