The 2009–10 Scottish Football League Third Division (also known as the 2009–10 Irn-Bru Scottish Football League Third Division for sponsorship reasons) was the 15th season in the format of ten teams in the fourth-tier of Scottish football. The season started on 8 August 2009 and ended on 1 May 2010. Livingston F.C. finished top and were promoted alongside Forfar Athletic as play-off winners.