A total of 140 shops closed in the country's main shopping destinations between January and July - an increase of 30% on the same period in 2018, PwC said.
The rate of new store openings also rose during this time however - up from 58 to 86.
Online retail, the impact of business rates and Brexit uncertainty were cited as reasons behind the closures.
Jason Higgs, head of business recovery services for PwC in Scotland, said: "In the last six months the sectors growing their presence on the high street are the likes of convenience stores, coffee shops and fast food restaurants; we are even seeing an increase in the number of bars after a long period of difficulty for the licensed trade.
"Casual dining has been one of the hardest hit sectors as consumers watch their spending.
"Going out for dinner is one of the first luxuries to go, and that has been reflected in the number of large restaurant chains facing challenges.
"The increase in new openings in Scotland from 58 to 86 is welcome news and indicates that with more vacant premises than a year ago, there may be favourable deals out there for retailers looking to expand, though what is good news for operators is bad news for landlords who are increasingly seeing requests for rent reductions through CVAs (Company Voluntary Arrangements)."
Across Scotland's cities, Dundee was the only without a net loss of shops - with four units closing and the same number of new openings.
Glasgow saw 46 closures offset by 34 openings, while Edinburgh saw 37 closures and 20 new openings.
In Aberdeen, 20 outlets closed and 13 opened, and the figure for Perth was 12 and seven respectively.
Falkirk lost three stores with no new openings over the six-month period, while in Paisley 10 shops closed and four opened, and in Ayr there were also four openings, against eight closures.
The research was compiled for PwC by the Local Data Company (LDC).
Retail sales figures also published on Wednesday showed a 0.2% decrease in August compared with the same month last year.
Food sales increased, but the Scottish Retail Consortium said customers remain unwilling to commit to expensive purchases.
Ewan MacDonald-Russell, head of policy and external affairs at the SRC, said: "Scottish retail sales were stuck in a holding pattern in August as the continued squeeze on consumer spending and political uncertainty continued.
"There were some bright moments in the month where the rare bursts of sunshine encouraged sales of outdoor food and drinks, but that was offset by weak non-food sales.
"Retailers will therefore be looking forward cautiously to the autumn. Our expectation is customer spending will continue to be focused on essentials, and therefore we'd hope Government would ensure there were no further immediate costs which would stretch hard-pressed retailers even further."