CTR may stand for:
- Institutions
- Cryptologist (Collections), Rate designator for Signals Intelligence Collections & Analyzation, United States Navy
- Computing Tabulating Recording Company, a company that was renamed IBM in 1924
- Center for turbulence research, a research institute at Stanford University
- In business
- Click-through rate, a measure of the success of an online advertising campaign
- Currency transaction report, a report about transactions that the Bank Secrecy Act requires banks to file with the Internal Revenue Service
- Contractor, commonly used in the US Federal Government, as contrasted to Employee
- Cars
- Civic Type R, a car manufactured by Honda
- Ruf CTR, a car by Ruf Automobile of Germany
- In technology and science
- Counter mode, a mode of operation for block ciphers
- X-ray crystal truncation rod, a technique to measure properties of crystal surfaces
- In Medicine
- Cardio-thoracic ratio
- Clinical trials registry
- Other
- Nunn–Lugar Cooperative Threat Reduction is an initiative to secure and dismantle weapons of mass destruction and their associated infrastructure in former Soviet Union states.
- The national rail station code for Chester railway station.
- Competitive trail riding, an equestrian sport
- Choose the right, a common Latter Day Saint saying, often found on a CTR ring
- Nunn-Lugar Cooperative Threat Reduction, a US policy of providing support for decommissioning of Soviet weapon stockpiles
- Control Zone, a controlled airspace zone, typically around airports
- CTR is the ICAO airline designator for Aerolíneas Centauro, Mexico
- Crash Team Racing, a 1999 video game for the Sony PlayStation, developed by Naughty Dog
- A Close Target Reconnaissance, a term used by ground forces to describe scouting in extremely close proximity to the target.