The 2018–19 Northern Arizona Lumberjacks men's basketball team represented Northern Arizona University during the 2018–19 NCAA Division I men's basketball season. The Lumberjacks were led by seventh-year head coach Jack Murphy and played their home games at the Walkup Skydome in Flagstaff, Arizona as members of the Big Sky Conference. They finished the season 10–21, 8–12 in Big Sky play to finish in a tie for eighth place. They lost in the first round of the Big Sky tournament to Sacramento State.