A2 can refer to:

• The A2 highway in Austria.
• The A2 road in England.
• The A2 (road) in Portugal.
• The A2 highway in Germany.
• The A2 highway in Switzerland.
• The (German) Stereo sound system used in some countries for their analogue television broadcasting. It is also known as Zweiton . See also: NICAM.
• The A2-level education qualification in England, Wales and Northern Ireland.
• A street name for the drug benzylpiperazine (BZP).
• A2, a German design of rocket during World War II
• A2 is an international standard paper size (420×594 mm), defined in ISO 216.
• The A-2 or AJ Savage aircraft.
• A-2 , a programming language created by Grace Hopper
• HMS A2, an A-class submarine of the Royal Navy.
• USS A-2, a Plunger-class submarine of the United States Navy.