The 2009–10 Scottish First Division was the 16th season of the First Division in its current format of ten teams.
In the first half of the season each team plays every other team twice (home and away) and then does the same in the second half of the season.
Times are BST (UTC+1) The ninth placed team in the First Division played the fourth placed team in the Second Division and third placed team in the Second Division played the second placed team in the Second Division.
The play-offs were played over two legs, the winning team in each semi-final advanced to the final.
The winning team was awarded a place in the 2010–11 First Division.