AP, Ap, or ap are acronyms, initialisms, or abbreviations that may refer to:

• Associated Press, an American news agency.
• Advanced Placement, a high school program.
• Andhra Pradesh, a state in south India.
• An access point, similar to a hub used in Ethernet networking but using wireless technologies.
• Acetone peroxide, an explosive.
• Amiga Power, a defunct monthly computer magazine about amiga computer games.
• Acción Popular ("Popular Action"), a political party in Peru.
• Alianza Popular ("Popular Alliance"), a political party in Chile.
• The U.S. military state code for personnel in the Pacific Ocean region.
• The U.S. Navy hull classification symbol for "transport."
• Assistant principal.
• Armour-piercing shot or shell.
• Ap, a nickname for the comic book character Apathy Kat.