The 14th Theoretical Aspects of Software Engineering Conference (TASE 2020) will be held in Hangzhou City, China on 15-17 July 2020. Modern society is increasingly dependent on software systems that are becoming larger and more complex. This poses new challenges to the various aspects of software engineering, for instance, software dependability in trusted computing, interaction with physical components in cyber physical systems, quality assurance in AI systems, distribution in cloud computing applications, security and privacy in general. Hence, new concepts and methodologies are required to enhance the development of software engineering from theoretical aspects. TASE 2020 aims to provide a forum for people from academia and industry to communicate their latest results on innovative advances in software engineering. The proceedings of the TASE 2020 symposium are planned to be published by the IEEE Computer Society Press. The authors of a selected subset of accepted papers will be invited to submit extended versions of their papers to a special issue of the Science of Computer Programs journal.