This book constitutes the refereed proceedings of the 9th International Symposium on End-User Development, IS-EUD 2023, held in Cagliari, Italy, during June 6–8, 2023.The 17 full papers and 2 (keynote extended abstracts) included in this book were carefully reviewed and selected from 26 submissions. They were organized in topical sections as follows: ​Artificial Intelligence for End-Users; Internet of Things for End-Users; Privacy; Security and Society; Supporting End-User Development.