Ixcatec (in Ixcatec: xwja o xjuani) is a language spoken by the people of the Mexican village of Santa María Ixcatlan, in the northern part of the state of Oaxaca. The Ixcatec language belongs to the Popolocan branch of the Oto-manguean language family. It is believed to have been the second language to branch off from the others within the Popolocan subgroup, though there is a small debate over the relation it has to them.

195 people reported speaking the language in the 2020 census, but according to the Consejo Nacional para la Cultura y las Artes, there were only 8 speakers of the language in 2008. In 2010, 190 speakers of Ixcatec were registered. In 2020, there were 195 speakers of Ixcatec. The small number of current speakers is the result of a steady decline over the last 60 years, which can be attributed to anti-illiteracy campaigns by the Mexican government that discouraged the use of indigenous languages, migration from the area to the cities, and the small initial population of speakers of the language.

Despite the lack of historical documentation in Ixcatec, written speech has been observed to use Latin script following the arrival of the Spaniards. The earliest document written in Ixcatec is from 1939, when native speaker Doroteo Jiménez wrote a letter to Lázaro Cárdenas, the president of Mexico from 1934 to 1940. Later on, an orthography for the language had begun development in the 1950s with reliance on the Spanish alphabet when necessary.

Ixcatec derives its name from the Nahuatl word ichcatl meaning 'cotton'. In Spanish it can be referred to by the term ixcateco, in which the added on suffix -teco stems from the Nahuatl suffixes -teca/-tecatl which means 'inhabitant of a place', especially one with a name ending in -tlan or -lan. This term can be traced back to the eighteenth century.