The 28th Ada-Europe International Conference on Reliable Software Technologies (AEiC 2023) will take place in Lisbon, Portugal. The conference presentations will illustrate current work in the theory and practice of the design, development, and maintenance of long-lived, high-quality software systems for a challenging variety of application domains. The program will allow ample time for keynotes, Q&A sessions and discussions, and social events. Participants include practitioners and researchers from industry, academia, and government organizations active in the promotion and development of reliable software technologies.