TMR may refer to:
- IATA airport identifier for Aguenar – Hadj Bey Akhamok Airport
- Triple modular redundancy, redundancy using three systems and voting to determine the result
- Tunnel magnetoresistance, in effect occurring when two ferromagnets are separated by a thin insulator
- Rolls-Royce Thrust Measuring Rig, a platform designed to investigate vertical take-off flight
- TM Revolution, the Japanese musician Takanori Nishikawa, performing as T.M.Revolution
- Town of Mount Royal, a town in the province of Quebec, Canada
- The Talented Mr. Ripley, 1955 novel
- The Talented Mr. Ripley, 1999 film
- The Talented Mr. Roto (Matthew Berry), a fantasy football expert on ESPN.com
- Name for the programmable timer resource in the PIC microcontroller
- Jewish Babylonian Aramaic via its ISO-639 code
- The Maccy Rays
- Trout Mask Replica, an album by Captain Beefheart
- Tom Marvolo Riddle, birth name of Harry Potter antagonist Lord Voldemort
- Total Mixed Ration, a method of feeding cattle.
- Short for tomorrow, see Internet slang
- The Ten Mile Run, a stream in New Jersey
- The Medical Record, a clinical record system developed at Duke University
- Time to Maximum Rate, a chemical process safety term