1999 Northern Arizona Lumberjacks football team

The 1999 Northern Arizona Lumberjacks football team was an American football team that represented Northern Arizona University (NAU) as a member of the Big Sky Conference (Big Sky) during the 1999 NCAA Division I-AA football season. In their second year under head coach Jerome Souers, the Lumberjacks compiled an 8–4 record (6–2 against conference opponents), outscored opponents by a total of 409 to 370, and tied for second place in the Big Sky. The Lumberjacks were invited to play in the NCAA Division I-AA Football Championship playoffs, where they lost in the first round to eventual national champion Georgia Southern by a 72–29 score.

Northern Arizona later forfeited four conference victories—over, Montana State, , and Cal State Northridge—due to use of ineligible player. This dropped their overall record to 4–8 and put them in the last-place tie in the Big Sky at 2–6.

The team played its home games at the J. Lawrence Walkup Skydome, commonly known as the Walkup Skydome, in Flagstaff, Arizona.