This book CCIS 2369 constitutes the proceedings of the Third International Workshop on Collaboration in Knowledge Discovery and Decision Making, DECISIONING 2024, held in Pereira, Colombia, during June 4-6, 2024. The 18 full papers were carefully reviewed and selected from 54 submissions. These papers explore recent advances in collaborative decision making and knowledge discovery, addressing topics including data analysis, artificial intelligence, decision models and industrial applications.