Elections Ontario says unofficial results show 31,399 voters opted to decline their ballots — the highest amount since 1975.
The agency says it also counted 22,687 rejected ballots and 12,059 unmarked ballots from the June 12 election.
Elections Ontario spokesman Andrew Willis says a declined ballot is different from an unmarked one because it involves a voter actively informing an officer at the poll that they are choosing to decline to vote.
The officer will then marked the ballot as a declined one and count it separately from rejected or unmarked ballots.
The Liberals won a majority in the election, securing 58 seats, while the Progressive Conservatives won 28 seats and the NDP got 21.
Voter turnout edged up to 52.1 per cent, compared to 48.2 per cent in the last election in 2011.