The 2021 Stephen F. Austin Lumberjacks baseball team represented Stephen F. Austin State University during the 2021 NCAA Division I baseball season. The Lumberjacks played their home games at Jaycees Field and were led by thirteenth–year head coach Johnny Cardenas. They were members of the Southland Conference. This was Stephen F. Austin's final year in the Southland as they will be moving to the Western Athletic Conference for the 2022 season.