Texinfo is a typesetting syntax used for generating documentation in both on-line and printed form (creating filetypes as dvi, html, pdf, etc., and its own hypertext format, info) with a single source file. It is implemented by a computer program released as free software of the same name, created and made available by the GNU Project from the Free Software Foundation.

The main purpose of Texinfo is to provide a way to easily typeset software manuals. Similar to the LaTeX syntax, all the normal features of a book, such as chapters, sections, cross references, tables and indices are available for use in documents. Using the various output generators that are available for Texinfo, it is possible to keep several documentation types up-to-date (such as on-line documentation provided via a Web site, and printed documentation, as generated using the TeX typesetting system) using only a single source file.

The official Texinfo documentation states that the first syllable of "Texinfo" is pronounced so as to rhyme with "speck", not "hex"; this pronunciation is derived from the pronunciation of TeX, in which the X represents the Greek letter chi rather than the English letter x. The maintainers state that "Texinfo" should be written with only a capital "T" and the rest of the letters in lower case.