This open access book constitutes the proceedings of the 6th Nordic e-Infrastructure Collaboration Conference, NeIC 2024, which took place in Tallinn, Estonia, in May 2024.  The 14 papers included in this book were carefully reviewed and selected from 39 submissions. They deal with e-infrastructure focusing on topics like FAIR data stewardship, high-performance computing (HPC), sensitive data management, federated resource management, quantum computing, and AI-driven e-infrastructure solutions.