Deputy First Minister Nicola Sturgeon confirmed the additional cash for the Help to Buy (Scotland) scheme - taking the total funding it has received to £275 million.
The initiative has already helped more than 1,100 people buy a new home since it was introduced in September last year.
It has also provided "much needed economic growth" by boosting the construction industry, Ms Sturgeon said.
"This additional £40 million funding will allow more people in Scotland to buy their first home and continue to make it easier for 'second-steppers' and others to move to a new property," she said.
"Since it launched in September last year, our Help to Buy scheme has already helped over 1,000 households into home ownership and this additional funding will benefit even more families.
"It is also bringing much needed economic growth to Scotland by supporting our housing industry and creating employment opportunities. This is alongside our continued commitment to investing in affordable housing for communities across Scotland.''
Help to Buy allows both first-time buyers and existing homeowners buying a new-build house from a participating builder to get up to 20% of their purchase price.
The Scottish Government then takes out an equity stake in the property which the buyer has to repay at a later date.
Sandy Adam, the chair of New Homes for Scotland, said: "A significant proportion of new homes are now sold through Help to Buy, delivering on the Scottish Government's key objectives of providing more homes, creating more jobs and stimulating the economy.
"Additional investment, such as that announced today, and longer term support assisting developers with investment planning will help the industry to, quite literally, build on the scheme's initial success and step up production to the levels required to meet housing need across all tenures.
"But this welcome boost for Help to Buy (Scotland) is valuable in another way. Many people in Scotland want to own their own home. Raising aspiration and confidence in this way can only be achieved through initiatives such as this."
The Royal Institution of Chartered Surveyors also welcomed the funding, with Scotland director Sarah Speirs saying: "The property market has seen an upturn in recent months, in part due to Help to Buy, as well as better lending and borrowing conditions.
"Helping those who can't afford large deposits by using the Government's balance sheet to guarantee mortgages and using capital savings to offer shared equity loans on new build for all buyers can go some way to help prevent prolonged market stagnation."
But she added: "Other areas within the residential market also need addressed, particularly the lack of supply as demand continues to grow with investment in these initiatives. The Scottish Housing Commission will publish a detailed report and recommendations on the Scottish housing market in June 2014."