Norges Teknisk-naturvitenskapelige Universitets Idrettsforening, NTNUI, is the largest sports club in Norway with more than 10,000 members and a variety of participators on all levels of skills in more than 50 different sports. The athletic association is formally connected to the Norwegian University of Science and Technology located in Trondheim. The club has facilities at Dragvoll, Gløshaugen, Moholt and Solsiden.
The club was formed after the merge of several educational institutions in 1996, which resulted in the university NTNU. The largest of the merging sports clubs was NTHI.
NTNUI's cross-country skiing group is the sports club with the highest number of participants in the Norwegian ski marathon Birkebeinerrennet (170 participants in 2010).