RR

RR, Rr or rr may refer to:

Arts and entertainment

 * RR (film), a 2007 experimental film by James Benning
 * Red Ribbon Army, a fictional army in the Dragon Ball series
 * Ruff Ryders Entertainment, a record label and East Coast rap collective
 * Fury from the Deep (production code: RR), a 1968 Doctor Who serial
 * RR (EP), a 2023 collaborative EP by Rosalía and Rauw Alejandro
 * RR, prefix for models of Jackson Rhoads electric guitars commissioned by guitarist Randy Rhoads

Businesses and organizations

 * Rashtriya Rifles, an Indian counter-insurgency force
 * Rational Recovery, an addiction recovery program
 * Rekords Rekords (logo), an American record label
 * Rhodesia Regiment, Rhodesian Army unit
 * Royal Air Force (IATA airline designator)
 * Richard Rohac (logo), an Austrian art metal firm

Language

 * rr (digraph)
 * Revised Romanization of Korean, the official Korean language romanization system in South Korea
 * Revised Romanization of Hangeul, the former official Hangeul language romanization system in South Korea

Science and technology

 * ITU Radio Regulations
 * Rapid Refresh (weather prediction), a short-range numerical weather prediction model
 * Rear-engine, rear-wheel-drive layout, in automotive design
 * Recoilless rifle

Biology and medicine

 * RR, an Rh factor phenotype
 * "RR", a blood pressure measurement taken with a sphygmomanometer invented by Scipione Riva-Rocci
 * RR interval (R wave to R wave interval), the inverse of heart rate
 * Risk ratio, or relative risk, in statistics and epidemiology
 * Respiratory rate, a vital sign
 * Roundup Ready, Monsanto line of genetically modified crop seeds

Computing

 * Resource record, in the Domain Name System
 * Round-robin scheduling, an algorithm for coordinating processes in an operating system
 * Route reflector, a Border Gateway Protocol configuration
 * rr (debugging), a record and replay debugger for userspace Linux programs

Sports

 * Rajasthan Royals, an Indian Premier League franchise
 * Ranchi Rhinos, a defunct Hockey India League franchise
 * Run rate, an average number of runs a batsman (or the batting side) scores in an over of 6 balls in cricket

Transportation

 * Raritan River Railroad (reporting mark: RR)
 * Buzz (Ryanair) (IATA code: RR), a Polish airline subsidiary of Ryanair Holdings
 * Regional Road, a class of road in Ontario
 * Rhodesia Railways, former Zimbabwean railway company
 * Rhymney Railway, former British railway company
 * Rolls-Royce Holdings (LSE code and logo)
 * Rolls-Royce, several companies


 * RR, a predecessor of the R (New York City Subway service)