TMSR, as an acronym, may refer to:
Indian drama Tera Mera Saath Rahe, 2021 TV series Tera Mera Saath Rahen, 2001 film
Music The Most Serene Republic, Canadian indie rock group
Sports TMS Ringsted, Danish handball club
Thorium molten salt reactor TMSR 500, prior designation of the ThorCon nuclear reactor TMSR (Chinese reactor project) TMSR-LF1, active experimental reactor