| Acronym | Definition |
|---|
| ARPA | Advanced Research Projects Agency (US DoD; now DARPA) |
| ARPA | Address and Routing Parameter Area |
| ARPA | Automatic Radar Plotting Aid |
| ARPA | Agenzia Regionale Protezione Ambiente (Italian: Regional Agency for the Protection of Environment) |
| ARPA | Amazon Region Protected Areas |
| ARPA | Archaeological Resources Protection Act of 1979 |
| ARPA | Agricultural Risk Protection Act of 2000 |
| ARPA | American Review of Public Administration |
| ARPA | Alberta Recreation and Parks Association |
| ARPA | Australian Retired Persons Association |
| ARPA | Association Rissoise de Protection des Animaux |
| ARPA | Alabama Recreation and Parks Association |
| ARPA | Australasian Religious Press Association |
| ARPA | Australian Rehabilitation Providers Association |
| ARPA | Arizona Rail Passenger Association |
| ArPA | Arkansas Psychological Association |
| ARPA | Atlantic Region Philosophers Association (Canada) |
| ARPA | Arkansas Rifle & Pistol Association |
| ARPA | Astoria Railroad Preservation Association (Astoria, OR) |
| ARPA | Advanced Radar Plotting Aid |
| ARPA | Alaska Recreation and Park Association |
| ARPA | Austrian Research Promotion Agency |
| ARPA | Arctic Research and Policy Act of 1984 |
| ARPA | African Revenue Protection Association |
| ARPA | Arkansas Recreation and Parks Association |
| ARPA | Airbreathing and Rocket Propulsion Analysis (tool for space vehicle design) |
| ARPA | Amicale Rétro Peugeot Atlantique (French car club; Nantes, France) |
| ARPA | Autolinee Regionali Pubbliche Abruzzesi SpA |
| ARPA | American Red Poll Association |
| ARPA | Arizona Rock Product Association |
| ARPA | Aachener Rechner-Pools Audimax |
| ARPA | Area Radar Prediction Analysis |
| ARPA | Association for Reformed Political Action |
| ARPA | Average Revenue Per Account |
| ARPA | Association Rwandaise des Personnes Agees (French) |
| ARPA | Army Research Projects Agency |
| ARPA | Association of Rights Protected Artists |
| ARPA | Analysis, Research & Planning for Armenia (Granada Hills, CA) |
| ARPA | Approval of Regulatory Program Amendments |
| ARPA | Austalian Prudential Regulation Authority |