ATAC, or Atac, may refer to:

• Airborne Tactical Advantage Company, a U.S. government contractor which operates foreign military aircraft for training purposes

• Anti-Terrorist Action Command, a fictional police organization in the 1981 movie Nighthawks

• Navy Antiterrorist Alert Center, the 1983–2002 United States Navy terrorism watch center

• "Arimidex, Tamoxifen, Alone or in Combination", an international trial of treatments for localized breast cancer

• Asbestos Testing and Consultancy Association, a UK trade association

• Assay for Transposase-Accessible Chromatin (ATAC-seq), a DNA sequencing technique

• Atac, a French supermarket chain

• ATAC SpA (), a public transport company in Rome, Italy

• Automatic targeting attack communicator, a fictional military communication device in the James Bond movie For Your Eyes Only

• Advanced Technology Airborne Computer (ATAC) was a computer used on US naval aircraft and the NASA Galileo (spacecraft).

See also

• Ataç, list of people with a similar Turkish name