The National Autonomous University of Mexico (Spanish: Universidad Nacional Autónoma de México, UNAM) is a public research university in Mexico. It has several campuses in Mexico City, and many others in various locations across Mexico, as well as a presence in nine countries. It also has 34 research institutes, 26 museums, and 18 historic sites. With more than 324,413 students, UNAM is one of the world's largest universities.

A portion of Ciudad Universitaria (University City), UNAM's main campus in Mexico City, is a UNESCO World Heritage site that was designed and decorated by some of Mexico's best-known architects and painters. The campus hosted the main events of the 1968 Summer Olympics, and was the birthplace of the student movement of 1968. All Mexican Nobel laureates have been alumni of UNAM. In 2009, the university was awarded the Prince of Asturias Award for Communication and Humanities. More than 25% of the total scientific papers published by Mexican academics come from researchers at UNAM.

UNAM was founded in its modern form, on 22 September 1910 by Justo Sierra as a secular alternative to its predecessor, the Royal and Pontifical University of Mexico (the first Western-style university in North America, founded in 1551).