The workshop will focus on core software engineering issues in the context of service-oriented systems and especially focus on modern trends of cloud native microservices and associated DevOps approaches. Our aim is to facilitate exchange and evolution of ideas in service engineering research across multiple disciplines and to encourage participation of researchers from academia and industry. WESOACS 2018 continues a successful series of workshops that started at ICSOC 2005 in Amsterdam. Over the last thirteen years WESOA/CS has demonstrated its relevance by attracting a large number of participants and producing high-quality papers that were published by Springer LNCS series. The WESOACS series encourages radically new approaches that address challenges arising from unique characteristics of service-oriented applications and cloud services, focusing on principles, methodologies, techniques and tools that support a service-oriented system development life cycle.