This two-volume set LNAI 14839-14840 constitutes the refereed proceedings of the International Joint Conference on Rough Sets, IJCRS 2024, held in Halifax, NS, Canada, during May 17-20, 2024. The 43 full papers included in this book were carefully reviewed and selected from 56 submissions. They are organized in topical sections as follows: Part I: Rough Set Models and Foundations; Rule Induction and Machine Learning; Granular Computing; and Rough Set Applications. Part II: Three-Way Decision and Rough Sets; Three-Way Decision in Data Analytics; Three-Way Decision in Broad Senses; Rental Market Data Mining; and Applications of Deep Learning and Soft Computing.