| ATN | Attention (IEEE-488 / IEC-625 Interface Bus) | |
| ATN | Ann Arbor (Amtrak station code; Anniston, AL) | |
| ATN | Acute Tubular Necrosis | |
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| ATN | Asian Television Network | |
| ATN | Air Tahiti Nui | |
| ATN | Australasian Transport News | |
| ATN | Aids to Navigation (shipping) | |
| ATN | All Together Now (Beatles song) | |
| ATN | Application Transport Network (computing) | |
| ATN | Amateur Television Network (FastScan) | |
| ATN | Acetonitrile | |
| ATN | Aeronautical Telecommunications Network | |
| ATN | Augmented Transition Network | |
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| ATN | Automated Trust Negotiation (sensitive information protocols) | |
| ATN | Across the Nightmare (Dance Dance Revolution song) | |
| ATN | Atlantic Tele-Network, Inc. (also seen as ATNI; Beverly, MA) | |
| ATN | Advanced Tiros N (satellite) | |
| ATN | Africa Trade Network | |
| ATN | Australian Television Network (Sydney, Australia) | |
| ATN | Arriva Trains Northern (UK train operator) | |
| ATN | Air Traffic Network | |
| ATN | Action Performance Companies, Inc. (stock symbol; Phoenix, AZ) | |
| ATN | Agri-Food Trade Network (Canada) | |
| ATN | Air Technology Network | |
| ATN | Australian Tourism Net (travel guide) | |
| ATN | Albinism, Tyrosinase-Negative | |
| ATN | Advanced Television Infrared Observation Satellite | |
| ATN | Automatic Track Number (SYS-1) | |
| ATN | Adaptive Tactical Navigation | |
| ATN | Ausbildungs- und Tätigkeitsnachweis (German: training and activity proof, water emergency service) | |
| ATN | Assign Thresholds (US DoD) | |
| ATN | Acyclic Transmission Network | |
| ATN | AgTa1-xNbxO3 (Silver tantalate niobate; ferroelectric material) | |
| ATN | Astrophysical Teletype Network | |
| ATN | Application Technologies Nouvelles (French: Application for New Technologies; est. 1986) | |
| ATN | Accelerator Technical Note | |
| ATN | Aviation Electronics Technician Radio and Radio Nav Equipment (US Navy) | |
| ATN | Account Telephone Number | |