BZ may stand for:

• 3-quinuclidinyl benzilate, an odorless military incapacitating agent
• Belize (ISO 3166-1 alpha-2 country code)
• Benzodiazepines
• Bz - benzoyl group (chem.) C₆H₅-CO- . The functional group - acyl derived from benzoic acid
• bzip2

busy*internet slang)