Figures for 2015 show 14% of all households rent their property from either a private landlord, or a family member, friend or their employer, compared to 5% in 1999.
The latest Scottish Household Survey found 61% of people are owner-occupiers - the same proportion as in 1999 but down from the high of 66% which was last recorded in 2009.
Less than a quarter (23%) of households are living in either a council or housing association property, compared to 32% 16 years ago.
The overall number of households in Scotland has increased 11% from 2.19 million in 1999 to 2.43 million in 2015.
More than two-fifths (43%) of private renters have been in their home for less than a year, the 2015 survey found, while more than half (53%) expect to move in the next five years.
The housing charity Shelter Scotland said the research is “further confirmation” that continued reforms are needed in the private rental sector to make it “more modern, stable, flexible and fairer for everyone that calls it home”.
Spokesman Adam Lang said: “Private renting in Scotland has tripled since 1999 with 350,000 households calling the sector home - including 91,000 with children.
“This growth along with major changes to the type of people now renting privately meant reform of the sector was vital. Shelter Scotland has been spearheading the push for reform to bring greater protection and increased security and fairness for tenants.
“Progressive and far-reaching changes in the laws on private renting - such as the new private tenancy - are a big step forward and will have a profound impact on how the sector is run.
“The challenge now is to enforce the legislation and to see that poorly performing landlords are supported to improve their practice and the worst landlords are removed from the sector.”
The survey also found fewer people are satisfied with the key public services of health, schools and public transport - with the proportion happy with all three falling from 62% in 2014 to 58% in 2015.
Satisfaction with schools has dipped over the last four years, from a high of 85% in 2011 to the current level of 74%.
Across Scotland, the survey found 94.6% of people rate their neighbourhood as a fairly good or very good place to live - including 56.3% who describe it as “very good”.
But in the most deprived communities, 30% ranked their area in this way, compared to 77% of those in the least deprived parts of the country.
The number of households who said they are managing well financially increased from 52% in 2014 to 55% in 2015.
However almost a quarter (23%) of single parent families and 17% of single adults said they do not manage well financially, compared to the Scottish average of 10%.
The number of households connected to the internet remains unchanged at 80%, but the report found “gaps in internet access and use remain amongst certain groups including those in deprived areas, those in social housing and those on low incomes”.
The number of people going online while on the move, using devices such as tablets or smartphones, continues to rise, from 41% in 2014 to 45% in 2015. Meanwhile, 28% said they make personal use of the internet while at work.