| Acronym | Meaning |
| ASHRAE | American Society Of Heating |
| ASI | Advanced Study Institute (NATO) |
| ASIC | Application Specific Integrated Circuit |
| ASIDIC | Association Of Information And Dissemination Centers |
| ASIP | Aircraft Structural Integrity Program |
| ASIS | American Society For Information Science |
| ASIS | Aromatic Solvent-induced Shift |
| ASK | Amplitude Shift Keying |
| ASK | Apoptosis Signal-regulating Kinase |
| ASKA | Analog Sensitive Kinase Allele |
| ASLE | American Society Of Lubrication Engineers (USA |
| ASLEEP | Automated Scanning Low Energy Electron Probe |
| ASM | Advanced Scavenging Model (for Air Pollution) |
| ASM | American Society For Metals |
| ASM | Acoustic Surface Measurement |
| ASM | Activated-sludge Model |
| ASM | Autosampler Module |
| ASMA | Alpha-smooth Muscle Actins |
| ASMC | Aortic Smooth Muscle Cell |
| ASMC | Arterial Smooth Muscle Cell |
| ASMD | Atmospheric Sciences Modeling Division (US EPA) |
| ASME | American Society Of Mechanical Engineers |
| ASMO | Antisymmetrical Molecular Orbital |
| ASMS | American Society For Mass Spectrometry |
| ASMV | Australian Student Mineral Venture |
| ASNOM | Aperture Scanning Near-field Optical Microscopy |
| ASNT | American Society For Nondestructive Testing |
| ASO | Atomic Spin Orbital |
| ASODN | Antisense Oligodeoxynucleotide |
| ASOG | Anal. Soln. Of Groups |
| ASP | Auger Sputter Profiling |
| ASP | Activated Sludge Plant Or Process |
| ASP | Antisegregation Process |
| ASPCR | Allele-specific Polymerase Chain Reaction |
| ASPEN | Advanced System For Process Engineering (DOE Software Package) |
| ASPEN | Assessment System For Population Exposure Nationwide |
| ASPERA | Analyzer Of Space Plasma And Energetic Atoms (Mars Express Spacecraft) |
| ASPET | American Society For Pharmacology And Experimental Therapeutics |
| ASPG | Antisymmetrized Product Of Separated Geminals Approxn. |
| ASPRS | American Society Of Photogrammetry And Remote Sensing |
| ASPT | Av. Score Per Taxon |
| ASQ | Axle Shaft Quality |
| ASQC | American Society For Quality Control |
| ASR | Alkali-silica Reaction |
| ASR | Automobile Shredder Residue |
| ASRG | Analytical Spectroscopy Research Group |
| ASRL | Atmospheric Sciences Research Laboratory |
| ASS | Argininosuccinate Synthetase |
| ASSIST | Abstract Semi-Markov Specification Interface To The SURE Tool [propulsion] |
| ASSP | Aerosol Scattering Spectrometer Probe |