Lib Dem leader Willie Rennie made the plea after a Freedom of Information request revealed 23 councils across Scotland have a total of 20,027 long term vacant private sector properties - which have been empty for a minimum of six months.
These include 5,583 homes which have been empty for at least two years, 2,053 which have been unoccupied for five years and 927 that have been vacant for a decade.
Midlothian Council revealed it was aware of one property which had been empty since April 1993 - almost 25 years.
Liberal Democrats released the research just days after figures showed the number of children living in temporary accommodation had risen by 10% in one year.
There were 6,581 children living in temporary homes on September 30 last year, up by 594 compared with the same day in 2016.
The Scottish Government said it had committed £756 million to its Affordable Housing Supply Programme.
While new build homes cost an average of £100,000 to construct, the bill for refurbishing an empty property is significantly, at between £6,000 and £25,000, according to the Scottish Empty Homes Partnership.
Mr Rennie said: “The new figures we have released today show the potential to create many more homes by bringing neglected properties back into use.
“Thousands of houses and flats across the country have been empty for years on end. We have identified almost a thousand that have been out of use for over a decade. With the right incentives and help, many of these could be resurrected.”
He added: “It is typically far cheaper to renovate an existing home than it is to build a new one. That’s why Scottish Liberal Democrats are calling for the Scottish Government to introduce of a new help to renovate loan to get existing vacant properties up to scratch and back in use, boosting Scotland’s housing stock.”
According to the party’s figures 190 private homes in the Scottish Borders Council area have been empty for a minimum of 10 years, with 130 properties in Fife Council also unused in this time.
Scottish Liberal Democrat housing spokesperson Caron Lindsay said: “Bringing these empty properties back into use would help alleviate the suffering caused by homelessness.”
Housing Minister Kevin Stewart said: “Ensuring everyone has access to a safe, warm and affordable place to call home lies at the heart of our ambition for a fairer Scotland.
“Core to that is our commitment to deliver at least 50,000 affordable homes over this Parliament.
“While that is challenging, we have shown before that we can deliver. That is why we have committed more than £756 million this year for our Affordable Housing Supply Programme.”