Labour spent just £337,000 during the 2016 Scottish Parliament campaign - less then half of the £880,000 which the party spent at the last election in 2011.
The vote saw Kezia Dugdale's party beaten into third place by the Scottish Conservatives who won 30 seats, compared with Labour's 23.
And today's figures indicate that spending power played a key role in this outcome, with the Tories splashing out £979,000 during the campaign - more than a threefold increase on the £273,000 spent by Ruth Davidson's party in 2011.
The SNP remain the biggest spenders with an outlay of £1.46 million, even though the party lost its majority, which it secured in 2011, with lower costs of £1.14 million during the campaign six years ago.
Political parties contesting every constituency and region in Scotland had a maximum spending limit of £1.516 million.
Andy O’Neill, Head of the Electoral Commission in Scotland said: “The information we have published today completes the picture on campaign spending by political parties at the Scottish Parliament election. Voters can now see exactly how parties spent their money campaigning for their votes.”
Previous figures have shown that the Greens, who won six seats, spent £176,000. The Liberal Democrats who returned five MSPs had costs of £186,000.