The 2005–06 Scottish Football League Third Division was the 12th season in the format of ten teams in the fourth-tier of Scottish football. The season started on 6 August 2005 and ended on 29 April 2006. Cowdenbeath finished top and were directly promoted to the 2006–07 Scottish Second Division.
The 2005–06 season saw the introduction of the play-offs in which the ninth placed team of the Scottish Second Division would enter and knock-out tournament with the teams ranked second, third and fourth in the Scottish Third Division. Berwick Rangers, Stenhousemuir and Arbroath entered the play-offs against Alloa Athletic of the Second Division, who emerged play-off winners and avoided relegation.
Source: Soccerway Rules for classification: 1) points; 2) goal difference; 3) number of goals scored. (C) Champions; (P) Promoted Notes:
^The 2nd, 3rd and 4th placed teams will be entered into a play-off with the Second Division's 9th placed team. The winning team will be awarded a place in the 2006–07 Second Division, Alloa Athletic won the play-off to stay in the division.