Greetings and welcome to the 31st International Symposium on High-Performance Parallel and Distributed Computing (ACM HPDC 2023). We are once again convening as part of the ACM Federated Computing Research Conference (FCRC). HPDC is the premier forum for bringing forth the state-of-the-art in high-performance and distributed computing, and this year is no exception. HPDC'23 features research in extreme-scale computing systems, big data, edge computing, middleware, heterogeneous clusters, and scheduling, to list a few. Additionally, we showcase experiential research from real-world deployments and open-source tools and data research-works that are having an impact on how researchers and practitioners use and develop large-scale systems in practice. The conference values the tremendous effort involved in deploying real systems and applications, as well as the invaluable insights gained from live measurement and experimentation. This coupled with the foundational research is the hallmark of HPDC.