ATD

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), a standard Unix program
 * Azimuth tractor drive, a 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, a Thomas Pynchon novel
 * Association for Talent Development
 * Attention to Detail, a defunct British video game developer
 * the postal code of Attard, Malta