Appalachian State University (), or App State, is a public research university in Boone, North Carolina, United States. It was founded as a teachers' college in 1899 by brothers B. B. and D. D. Dougherty and the latter's wife, Lillie Shull Dougherty. The university expanded to include other programs in 1967 and joined the University of North Carolina System in 1971.

The university enrolls more than 21,500 students. It offers more than 150 bachelor's degrees and 70 graduate degree programs, including two doctoral programs. The university has eight colleges: the College of Arts and Sciences, the Walker College of Business, the Reich College of Education, the College of Fine and Applied Arts, the Beaver College of Health Sciences, the Honors College, the Hayes School of Music, and University College. It opened an additional campus in Hickory in 2023.

The Athletic Teams compete in the Sun Belt Conference, except for a few sports that compete in the Southern Conference, such as wrestling. The university's team name is the Mountaineers.