Jacques Lapointe, who has served as the province's auditor general since March 2006, announced Thursday he will leave his position as of Jan. 31.
Lapointe released a report in 2010 on constituency allowance spending that resulted in charges against four politicians, who later pleaded guilty to fraud and other related charges.
Premier Stephen McNeil said the report helped bring Lapointe's work into the public spotlight, but the auditor general will also be remembered for holding departments and cabinet ministers accountable.
"The followup he's been doing on a consistent basis, with what they've done with those recommendations, has caused departments to take those recommendations much more seriously than they were in the past and making sure the changes are being implemented," said McNeil.
Prior to his current post, Lapointe served as assistant deputy minister and chief internal auditor for the Ontario government.
McNeil said Lapointe consistently delivered on his mandate to ensure taxpayers' money was spent efficiently and properly.
He said the search for a new auditor general will begin shortly, and it's hoped the government will be close to filling the position by the time Lapointe retires.