The 2021 Northern Arizona Lumberjacks football team represented Northern Arizona University as a member of the Big Sky Conference during the 2021 NCAA Division I FCS football season.

They were led by third-year head coach Chris Ball and played their home games at the Walkup Skydome.

On July 26, 2021, during the virtual Big Sky Kickoff, the Lumberjacks were predicted to finish seventh in the Big Sky by both the coaches and media.

[1] The Lumberjacks had two players selected to the preseason all-Big Sky team.

Special teams Luis Aguilar – K