This book constitutes the refereed proceedings of the 29th International Working Conference on Requirements Engineering: Foundation for Software Quality, REFSQ 2023, which took place in Barcelona, Spain, during April 17-20, 2023.The 12 full technical design and scientific evaluation papers, 8 short research previews and vision papers, and 5 experience reports presented in this volume were carefully reviewed and selected from 78 submissions. They were organized in topical sections as follows: Requirements communication and conceptualization; NLP and machine learning for AI; RE for artificial intelligence; crowd RE; and RE in practice.