Rem or REM may refer to:

• R.E.M., an American rock band
• R.E.M. (EP), by the band Green
• "R.E.M." (song), by Ariana Grande

• Rapid eye movement sleep, a phase of sleep
• Roentgen equivalent man (rem), a unit of radiation dose equivalent
• REM (BASIC), an inline comment (REMark) in BASIC and some other computer languages
• Rare-earth metal
• Reflection electron microscope
• Reticular erythematous mucinosis, a skin disease
• Root em, a font-size measurement used with Cascading Style Sheets
• Real ear measurement, measurement of sound pressure level in a patient's ear canal developed when a hearing aid is worn
• Random effects model, a statistical model

• La République En Marche!, a French centrist political party
• Reichserziehungsministerium, in Nazi Germany, unofficially known as the Reich Education Ministry
• Reiss Engelhorn Museum, Germany
• Resource Extraction Monitoring, a UK-based non-profit organisation
• Rosicrucian Egyptian Museum, California, United States
• REM Island, an offshore platform and home of the pirate stations Radio and TV Noordzee

• Jakob Rem (1546–1618), Austrian Jesuit
• Rem Koolhaas (born 1944), Dutch architect
• Rem Vyakhirev (1934–2013), Russian manager
• Rem, pen name of Priscilla Hamby, illustrator and comic book artist

• Rem, an android in Logan's Run
• Rem, in Dream Hunter Rem
• Rem Saverem, in Trigun
• Rem, in Bobobo-bo Bo-bobo
• Rem (Death Note), a Shinigami in Death Note
• Rem Kaginuki, a devil in Dance with Devils
• Rem (Re:Zero), a character in the light novel/anime series Re:Zero − Starting Life in Another World
• Rem Galleu, in How Not to Summon a Demon Lord

• Rém, a village in Hungary
• Réseau express métropolitain, Greater Montreal rapid transit system
• Rem (mythology), an Egyptian fish god

• All pages with titles beginning with Rem
• All pages with titles containing Rem
• REM World, a fantasy/science fiction novel by Rodman Philbrick
• Rems (disambiguation)