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.