NN may stand for:

• Neural network
• Netscape Navigator
• Nevada Northern Railway
• An initialism for "Night Night" in internet slang, meaning "Good Night".
• NN, Inc.
• Nn, software (a newsreader) for reading Usenet news written by Kim F. Storm
• Nomen nescio, the Latin phrase for the unknown person.
• Nynorsk (or Nynorsk Wikipedia ).