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 In arts and media Writing and journalism L. J. Davis (1940–2011), American writer L. J. Greenberg (1861–1931), British journalist L. J. K. Setright (1931–2005), English journalist L. J. Smith (author) (born 1965), American author
Other arts L. J. Foret (1930–2002), American musician LJ Reyes (born 1987), Filipino actress L. J. Roberts (born 1980), American textile artist
In government and politics L. J. C. Daniels (1858–1949), American political activist L. J. Fellenz (1882–1941), American politician L. J. Forman (1855–1933), American politician L. J. Maxwell (1851–??), American politician L. J. Seneviratne (1899–??), Sri Lankan civil servant
In sports Basketball L.J. Cason (born 2006), American basketball player L. J. Cooke (1868–1943), American basketball coach LJ Cryer (born 2001), American basketball player L. J. Figueroa (born 1998), Dominican-American basketball player L. J. Hepp (born 1978), American basketball coach L. J. Peak (born 1996), American basketball player Larry Johnson (basketball, born 1969), American basketball player
American football L. J. Castile (born 1987), American football player L. J. Collier (born 1995), American football player L. J. Fort (born 1990), American football player LJ Martin, American football player L. J. McCray (born 1991), American football player L.J. McCray (defensive lineman) (born 2005), American football player L. J. Phillips (born 2004), American football player L. J. Shelton (born 1976), American football player L. J. Smith (born 1980), American football player Lawrence Jackson (born 1985), American football player
Other sports L. J. Hoes (born 1990), American baseball player L. J. Mazzilli (born 1990), American baseball player L. J. van Zyl (born 1985), South African athlete
In other fields L. J. F. Brimble (1904–1965), English botanist L. J. Hanifan (1879–1932), American economist L. J. Jenkins (born 1987), American cowboy L. J. Sevin (1930–2015), American venture capitalist
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