NO or no may stand for:

• In common speech, the word "no" denotes negation, disagreement or unacceptance.
• New Orleans (usually N.O.)
• No symbol
• Nitric oxide (NO)
• Nobelium (No), symbol for the chemical element
• normally open switch (NO or N.O.)
• Norway, ISO country code
• Norwegian language (ISO 639 alpha-2, no)
• No, a 2002 album by They Might Be Giants, as well as a song on that album
• Noh, a Japanese theatrical form
• №, the numero sign