AIP is a three-letter abbreviation with multiple meanings, as described below:

• Afghan Islamic Press, a news agency based in Pakistan.
• Astrophysikalisches Institut Potsdam^*
• Air-independent propulsion, submarine propulsion systems which do not require it to surface frequently.
• American Institute of Parliamentarians, an educational organization promoting the advancement of parliamentary procedure.
• American Institute of Physics, a professional body for American physicists.
• American Institute of Philanthropy, an American nonprofit charity watchdog and information service.
• American International Pictures, an American movie company.
• Australian Institute of Petroleum, an Australian trade organisation.
• Australian Institute of Physics, a professional body for Australian physicists.
• Aeronautical Information Publication
• Acute intermittent porphyria, a medical condition.
• Archive International Productions, a music label. ^*
• Agent Interaction Protocol, a protocol for interactions between agents in a multi-agent system.

AIP