NH2 or similar may refer to:
- Azanide (chemical formula )
- Amino radical (chemical formula )
- Nitrenium ion (chemical formula )
- Imide ion (chemical formula )
- Primary amide group (chemical formula )
- National Harbor–Alexandria Line (Route NH2), a WMATA bus line between Alexandria, Virginia and Prince George's County, Maryland
- National Highway 2 (India)
- New Hampshire's 2nd congressional district