Abr or ABR may refer to:
- Abr, a village in Iran
Technology:
- Available Bit Rate, a service used in ATM networks
- Average bitrate, the average amount of data transferred per second
- Area border router, in the Open Shortest Path First protocol
- Adaptive bit rate, a method of video transmission through the Internet
- Anaerobic baffled reactor, a type of decentralized wastewater system
Transport:
- Abercynon North railway station, a closed railway station formerly serving the village of Abercynon in the Cynon Valley, South Wales
- IATA code for Aberdeen Regional Airport, an airport east of Aberdeen, South Dakota, United States
- Air Contractors, a European freight airline
- Athens Line, a railroad operating in the U.S. state of Georgia
Other uses:
- Abron dialect, a major dialect of the Akan language of Central Ghana
- Addison Brown (1830–1913), American jurist and botanist (standard author abbreviation: A. Br.)
- American Board of Radiology
- Auditory brainstem response, an electrical signal evoked from the brainstem of a human or other mammal by the presentation of a sound
- August Burns Red, a metalcore band from Lancaster, Pennsylvania
- Australian Biblical Review, academic journal
- Australian Book Review, a literary magazine
- Australian Business Register, government body tasked with issuing Australian Business Numbers (ABNs) and maintaining the Register