DMDX is a free software program for language processing experimentation. It offers millisecond accuracy in the display of stimuli and in the measurements of reaction times. This tutorial provides information for basic setup and use of the program. Some sample scripts will be provided and explained. Readers are encouraged to read Forster and Forster (2003) for an introduction to the program, download the program to gain hands-on experiences, and join the user list for technical support and interaction with other DMDX users.