The 1909 LSU Tigers football team represented the LSU Tigers of Louisiana State University during the 1909 college football season. The LSU team posted a 6–2 record, losing to Southern Intercollegiate Athletic Association (SIAA) champion Sewanee and to an undefeated Arkansas. Notable victories include those over Mississippi and Alabama.

The LSU Tigers football program, also known as the Fighting Tigers, represents Louisiana State University in college football. The Tigers compete in the Football Bowl Subdivision (FBS) of the National Collegiate Athletic Association (NCAA) and the Western Division of the Southeastern Conference (SEC).