MSR may refer to:
Science and technology Macrophage scavenger receptor, a receptor found in macrophages Magnetic stripe reader, a device used to read magnetic stripe cards such as credit cards M–sigma relation, in astrophysics Mars sample return mission, a spaceflight mission to return rock and dust samples collected on Mars Mirror self-recognition, in animals through the mirror test Molten-salt reactor, an advanced nuclear reactor design
Computing Machine state register, a register used in PowerPC architectures Model-specific register, a feature in x86 processors Microsoft Reserved Partition, a space-management partition on a computer storage device Mining software repositories, a field that analyzes the rich data available in software repositories
Entertainment MSR Studios, a New York recording studio The Most Serene Republic, a Canadian indie rock band Metropolis Street Racer, a Dreamcast racing game Mid-season replacement, a television series that premieres in the second half of a traditional season Metroid: Samus Returns, a video game Mulder Scully Romance, the relationship of the main characters of the television series The X-Files March, Strathspey and Reel, common bagpipe tune set Monster Studio Records, The in-house music studio for Arknights Metal Scar Radio, The in-house music studio for Arknights: Endfield
Organizations and companies Market Street Railway (nonprofit), a historic preservation organization in San Francisco, California, U.S.
Microsoft Research, the research division of Microsoft Mountain Safety Research, a US company specializing in outdoor equipment Mouvement social révolutionnaire, the French fascist party Revolutionary Social Movement Movimiento Social Republicano, the Republican Social Movement political party in Spain MSR – The Israel Center for Medical Simulation, Israeli institute for Simulation-Based Medical Education
Places Misamis Oriental (ISO sub-national code), a province in the Philippines Most Serene Republic, a title in the name of various countries Montserrat (ISO 3166-1 code)
Transportation EgyptAir (ICAO designator), an Egyptian airline Main supply route, a military operations supply route Market Street Railway (transit operator), a defunct company in California, US Michigan Shore Railroad, US Muar State Railway, a defunct railway formerly operating in Malaya (now Malaysia) Mumbai Suburban Railway, India Muş Airport (IATA airport code), Turkey
Weapons Modern sporting rifle or AR-15 style rifle Modular Sniper Rifle, a sniper rifle produced by Remington Arms Magnum Sniper Rifle or Accuracy International Arctic Warfare, a bolt-action sniper rifle
Other uses
Market Stability Reserve, a part of the European Union Emissions Trading System Milan–San Remo, an annual bicycle race Mortgage servicing rights, the rights to collect mortgage payments from a borrower for the benefit of the lender Meyer Shank Racing, an American auto racing team