The volume at hand presents the Special Issue on “Software Quality for Modern Systems”. The Special Issue has been originally conceived within the context of the 3 rd International Conference on Automation of Software Test (AST 2022). The authors of the best papers accepted at AST 2022 have been invited to submit an extended version of their previous work. In addition, the editors have decided to keep the submissions open for any other contributions aligned with the objectives of the Special Issue. The main objective of the Guest Editors is to promote discussions leveraging software testing automation for improving various software quality attributes.