LJ may refer to:
Arts and media
- L. J. Burrows, a fictional character on the TV series Prison Break
- Lemon Jelly, a British electronica duo
- Library Journal, an American trade publication for librarians
- Linux Journal, an American monthly technology magazine
- LiveJournal, a Russian social networking service
Businesses and organizations
- LJ Air, a Chinese airline
- Jin Air, a South Korean airline (IATA code LJ)
- Lashkar i Jhangvi, a Muslim terrorist organization
People
- L. J. F. Brimble (1904–1965), English botanist
- L.J. Cason (born 2006), American basketball player
- L. J. Castile (born 1987), American football player
- L. J. Collier (born 1995), American football player
- L. J. Cooke (1868–1943), American basketball coach
- LJ Cryer (born 2001), American basketball player
- L. J. C. Daniels (1858–1949), American political activist
- L. J. Davis (1940–2011), American writer
- L. J. Fellenz (1882–1941), American politician
- L. J. Figueroa (born 1998), Dominican-American basketball player
- L. J. Foret (1930–2002), American musician
- L. J. Forman (1855–1933), American politician
- L. J. Fort (born 1990), American football player
- L. J. Greenberg (1861–1931), British journalist
- L. J. Hanifan (1879–1932), American economist
- L. J. Hepp (born 1978), American basketball coach
- L. J. Hoes (born 1990), American baseball player
- L. J. Jenkins (born 1987), American cowboy
- LJ Martin, American football player
- L. J. Maxwell (1851–??), American politician
- L. J. Mazzilli (born 1990), American baseball player
- L. J. McCray (born 1991), American football player
- L.J. McCray (defensive lineman) (born 2005), American football player
- L. J. Peak (born 1996), American basketball player
- L. J. Phillips (born 2004), American football player
- LJ Reyes (born 1987), Filipino actress
- L. J. Roberts (born 1980), American textile artist
- L. J. Seneviratne (1899–??), Sri Lankan civil servant
- L. J. K. Setright (1931–2005), English journalist
- L. J. Sevin (1930–2015), American venture capitalist
- L. J. Shelton (born 1976), American football player
- L. J. Smith (born 1980), American football player
- L. J. Smith (author) (born 1965), American author
- L. J. van Zyl (born 1985), South African athlete
- Larry Johnson (basketball, born 1969), American basketball player
- Lawrence Jackson (born 1985), American football player
Places
- La Jolla, San Diego, California
- La Jolla, Placentia, California
- Ljubljana, the capital of Slovenia
Science and technology
- System LJ, Gentzen's sequent calculus for intuitionist logic
- LaserJet, a printer brand name
- Lennard-Jones potential, a function used in chemical physics
- Lightweight Java, a programming language
Other uses
- "Long jump" athletics abbreviation in track and field
- Lj (digraph), a digraph used in some Slavic languages
- Lord Justice of Appeal, a type of judge in England and Wales
See also
- Lje, a letter of the Cyrillic script
- Ljay, a given name