DDX

DDX may refer to:


 * $${\mathrm{d} \over \mathrm{d}x}$$, a common notation for the differential operator with respect to a variable x
 * DD(X), former program name of a class of U.S. Navy destroyers
 * Differential diagnosis (DDx or D/Dx), a systematic method used to identify unknowns
 * Device Dependent X, graphics device drivers supporting 2D acceleration in the X.Org Server
 * DDX (chemistry), a collective name for DDT and its breakdown products DDE and DDD