The country goes to the polls on Thursday to elect a new cohort of MSPs after six weeks of electioneering.
Nicola Sturgeon led an SNP rally in Glasgow, while Kezia Dugdale and Ruth Davidson followed suit in Edinburgh.
The Lib Dems, Greens and UKIP also hit the streets in a final drive for support across Scotland.
Polling stations will be open from 07:00 until 22:00 on Thursday, with results expected in the early hours of Friday. In total, 73 constituency MSPs and 56 regional list MSPs will be elected.
Ms Sturgeon led a public rally in Glasgow city centre as the campaign entered its final hours.
The SNP leader said: "Tomorrow, people in Scotland have the opportunity to ensure the re-election of an SNP government with an ambitious plan to keep Scotland moving forward - including a £500m above-inflation boost to NHS spending, additional investment in closing the attainment gap in our schools and to grow our economy, creating more and better-paid jobs.
"But the only way to guarantee that we are able to implement our vision for Scotland is to cast both votes for the SNP when you go to the polls on Thursday."
Campaigning in Edinburgh, Labour leader Kezia Dugdale said she believed a Labour government at Holyrood could be "transformational" for Scotland.
She said: "I have three priorities for the next five years - use the new powers of our parliament to tax the richest 1% so we can invest in schools, and stop the cuts to public services.
"Every Labour MSP we send to Holyrood will stand for those priorities. Tomorrow, we can vote to stop the cuts."
Ms Davidson also rallied her supporters in Edinburgh, and said she would lead the Scottish Conservatives to finish ahead of Labour in Thursday's poll.
Ms Davidson urged the new Scottish government to deliver for the "devolution generation" voting for the first time on Thursday.
She said: "They may have been born in the devolution era, but can we really say that devolution has transformed their lives to the extent it might have?
"I do not believe we can. The devolution generation deserves better."
Lib Dem leader Willie Rennie gathered his activists at the party's headquarters in Edinburgh before a final day of campaigning.
Mr Rennie said: "This is not a time to be timid. Liberal Democrats are ambitious for Scotland but better does not just happen.
"If people want to see a step change in the way we treat mental ill health, urgent investment to ensure we meet our green targets and a transformational investment in education, they need to vote for it on Thursday and back the Scottish Liberal Democrats."
The Scottish Greens are criss-crossing the country in a final bid to drum up support.
Co-convenor Patrick Harvie joined fellow candidates in Edinburgh before travelling to Glasgow to help serve lunch to older people. He will also be taking part in a live question and answer session on the party's Facebook page.
Fellow co-convenor Maggie Chapman is to canvas voters at Aberdeen University and the city's bus and railway stations.
Mr Harvie said: "Our aim is Green representation for every region of Scotland. With Labour in decline and the SNP lacking a constructive challenge, it's never been more important to vote Green."
Meanwhile, David Coburn campaigned for UKIP outside the Longannet power station in Fife, which was shut down earlier in the year.
Mr Coburn said closing the coal-fired power plant was a "disaster" because Scotland needs a mix of fuel sources to produce steel, which he said couldn't happen if electricity was too expensive. He said he wanted Scotland to be "open for business".
He said he wanted to end the "chumocracy" at Holyrood, pledging to "shake up" the Scottish Parliament if elected and saying it would be impossible to fit a cigarette paper between the other parties.
Scotland's political leaders have set out on a final bid to win over voters on the last day of the Holyrood election campaign.