The 2023 Appalachian State Mountaineers football team represented Appalachian State University during the 2023 NCAA Division I FBS football season. The Mountaineers were led by fourth-year head coach Shawn Clark. Appalachian State played home games at Kidd Brewer Stadium on the school's Boone, North Carolina, campus, and competed as a member of the East Division of the Sun Belt Conference. The Appalachian State Mountaineers football team drew an average home attendance of 34,734 in 2023.
On November 28, 2022, defensive coordinator Dale Jones left the program.
On January 13, 2023, the Mountaineers hired Scot Sloan to be their defensive coordinator.
On January 16 Appalachian State hired Frank Ponce to be their offensive coordinator after 2022 offensive coordinator Kevin Barbay left to become the offensive coordinator at Mississippi State.
In the Sun Belt preseason coaches' poll, the Mountaineers were picked to finish in second place in the East division.
Offensive lineman Isaiah Helms and right safety Milan Tucker were named to the preseason All-Sun Belt first team. Offensive lineman Damion Daley was named to the second team.
The football schedule was announced on February 24, 2023.