RJ

RJ or Rj may stand for:

* R_J in astronomy can mean 'Jupiter radius' (approximately 71,398 km)
* RJ, a Raccoon in the comic strip and feature film Over The Hedge
* Rio de Janeiro, Brazilian state and city
* Randy Johnson Major League Baseball Player
* Royal Jordanian airlines, of Jordan (IATA Airline Designator), owner of RJ.com
* Registered jack (RJ11, RJ14, RJ45, etc)
* Regional Jet, 35- to 100-passenger short-haul airliner manufactured by companies such as Bombardier Aerospace (CRJ), Embraer (ERJ), BAE Systems Regional Aircraft (ARJ or RJ), or the ACAC consortium (ARJ).
* Rim Job
* The RC-135 Rivet Joint
* R.J. Reynolds Tobacco Company
* RJ Rosales, Australian-Filipino actor and singer
* R. J. Helton of "American Idol"
* In Star Trek, Rj is the chemical symbol for element-123, jamesium, named after Richard D. James
* Raffles Junior College
* Righteous Jams, a straightedge hardcore band from Boston
* RJ (Family Guy Character)
* Romeo and Juliet, one of Shakespeare's plays
* Richard Jefferson, NBA player of the New Jersey Nets
* Roy Jones Jr., a boxer
* Les Brasseurs RJ, a brewery from the Province of Québec