ATD may refer to:
Computing and technology Anthropomorphic test device, also known as a crash test dummy at (command) or @daemon (spelled "atd", lower case), standard Unix program Azimuth tractor drive, drive system for tugboats
Medicine and science 1,4,6-Androstatrien-3,17-dione, estrogen inhibitor Acute tryptophan depletion Anti-thyroid drugs or antithyroid agent
Other uses ATD Fourth World Against the Day, Thomas Pynchon novel Association for Talent Development, non-profit association Attention to Detail, defunct British video-game developer Postal code for Attard, Malta