IN, In or in may refer to:
Places
- India (country code IN)
- Indiana, United States (postal code IN)
- Ingolstadt, Germany (license plate code IN)
Businesses and organizations
- Independent Network, a UK-based political association
- Indiana Northeastern Railroad (Association of American Railroads reporting mark)
- Indian Navy, a part of the India military
- Infantry, the branch of a military force that fights on foot
- MAT Macedonian Airlines (IATA designator IN)
In science and technology
- .in, the internet top-level domain of India
- Inch (in), a unit of length
- Indium (symbol In), a chemical element with atomic number 49
- Intelligent Network, a telecommunication network standard
- Intra-nasal (insufflation), a method of administrating some medications and vaccines
- Integrase, a retroviral enzyme
Other uses
- Imperishable Night, the eighth official game in the Japanese Touhou series
- Indonesian language (former ISO 639-1 language code; "id" used since November 3, 1989)
- In Nomine, a title given to any of numerous short pieces of English polyphonic instrumental or vocal music during the 16th and 17th centuries