This book constitutes the proceedings of the 38th International Conference on Architecture of Computing Systems, ARCS 2025, held in Kiel, Germany, in April 2025.The 24 full papers presented together with 12 other papers in this volume were carefully reviewed and selected from 49 submissions. These papers have been categorized in the following sections: self-powered embedded  systems up to plant powered high-performance systems, new emerging and cross-cutting topics,such as autonomous and ubiquitous systems, reconfigurable computing, mathematical models, neural networks, and artificial intelligence.