The Software Quality Days (SWQD) conference started in 2009 and has grown to the biggest conferences on software quality in Europe with a strong community. The program of the SWQD conference is designed to encompass a stimulating mixture of practical presentations and new research topics in scientific presentations. The guiding conference topic of the SWQD 2018 is “Software Quality 4.0: Methods and Tools for better Software and Systems”, as novel technologies include new challenges and might require new and adapted methods and tools to support quality assurance activities early. The 6 full papers and 2 short papers presented in this volume were carefully reviewed and selected from 16 submissions. The volume also contains 2 invited talks. The contributions were organized in topical sections named: safety and security; requirements engineering and requirements-based testing; crowdsourcing in software engineering; software and systems architecture; experimentation in software engineering; and smart environments.