This volume LNCS constitutes the refereed proceedings of the 21st International Conference on Distributed Computing and Intelligent Technology, ICDCIT 2025, in Bhubaneswar, in India, in January 2025. ICDCIT is organized into two tracks: Distributed Computing (DC) and Intelligent Technology (IT). The DC track solicits original research papers contributing to the foundations and applications of distributed computing. The DC track PC accepted 10 papers (7 regular papers and 3 short papers), and the IT track PC accepted 8 regular papers, The conference presents and discusses results and ideas on the foundations and applications of distributed computing and intelligent technology.