MusiXTeX provides a set of macros, based on the earlier MusicTeX, for typesetting music with TeX. To produce optimal spacing, MusiXTeX is a three-pass system: etex, musixflx, and etex again. (Musixflx is a Lua script that is provided in the bundle.) The three-pass process, optionally followed by processing for printed output, is automated by the musixtex wrapper script.

The package uses its own specialised fonts, which must be available on the system for musixtex to run. The MusiXTeX macros are universally acknowledged to be challenging to use directly: the pmx preprocessor compiles a simpler input language to MusiXTeX macros.