NH4 or NH-4 or NH 4 may refer to:

  • Ammonium, the NH+
    4 ion in chemistry
  • National Highway 4 (India), a major National Highway in western and southern India
  • New Hampshire Route 4, a 3.78-mile (6.08 km) long state highway located in eastern Strafford County, New Hampshire, USA
  • New Hampshire's 4th congressional district, an obsolete electoral district in New Hampshire, USA
  • NH4 (film), an upcoming Indian film