This book constitutes the proceedings of the 25th International Working Conference on Requirements Engineering - Foundation for Software Quality, REFSQ 2019, held in Essen, Germany, in March 2019. The 13 full papers and 9 short papers in this volume were carefully reviewed and selected from 66 submissions. The papers were organized in topical sections named: Automated Analysis; Making Sense of Requirements; Tracelink Quality; Requirements Management (Research Previews); From Vision to Specification; Automated Analysis (Research Previews); Requirements Monitoring; Open Source; Managing Requirements Knowledge at a Large Scale; in Situ/Walkthroughs (Research previews).