Anthrax is an acute disease caused by the bacterium Bacillus anthracis.

Anthrax may also refer to:

• Bacillus anthracis, the bacterium responsible for anthrax, the disease
  • Anthrax toxin, the virulent proteins secreted by Bacillus anthracis
  • 2001 anthrax attacks in the US
• Anthrax (fly), a genus of bombyliid flies
• Anthrax (American band), an American thrash metal band formed in 1981
  • "Anthrax", a song by the band of the same name from their album Fistful of Metal
• Anthrax (British band), a British anarcho-punk band formed in 1980
• Anthrax, a fictional character seen in the video game Shrek SuperSlam
• Anthrax (2001 film), starring David Keith
• Castle Anthrax, a fictional fortress in the movie Monty Python and the Holy Grail
• Los Ántrax, a Mexican gang