People and things known as "Jem" include:
* Jem (singer), the stage name of the musician "Jemma Griffiths"
* Jem (TV series), a 1980s animated television series
* Jem (book), a 1980 book by Frederik Pohl
* a character in Harper Lee's "''To Kill a Mockingbird"''
* Ibanez JEM, an electric guitar model designed by musician Steve Vai
* a nickname for James, Jeremiah or Jeremy
People and things known as "JEM" include:
* Justice and Equality Movement, a now defunct Sudanese rebel group
* Jaish-e-Mohammed, militant Islamist group based in Pakistan.
* The ''Journal of Environmental Monitoring''
* The ''Journal of Experimental Medicine''
* The ''Journal of Electronic Materials''
See also: Gem and GEM