The 2008–09 TFF First League (also known as Bank Asya First League due to sponsoring reasons) was the second-level football league of Turkey and the 46th season since its establishment in 1963–64. At the end of the season in which 18 teams competed in a single group, Manisaspor and Diyarbakırspor, which finished the league in the first two places, and the play-off winner Kasımpaşa were promoted to the upper league, while Sakaryaspor, Güngören Belediyespor and Malatyaspor, which were in the last three places, were relegated.