The Scottish Retail Consortium (SRC) and KPMG Retail Sales Monitor found total sales fell by 1.5% last month, compared with November 2015.
However, when adjusted for deflation, sales were found to have risen by 0.2% in real terms.
Total food sales were found to be flat on last November, while non-food dropped 2.7% compared with a year ago.
SRC said figures for the last three months had been "promising".
Director David Lonsdale said: "Total retail sales in Scotland recorded a third successive month of real-terms positive growth, albeit at a pace less marked than in October.
"This promising news was underpinned by further improvements in grocery sales, which grew for a third month in a row - the best quarterly performance in almost three years.
"Non-food sales were heavily driven by online sales arising from Black Friday.
"Promotional and discounting activity by retailers around cyber-weekend led to electricals and electronic goods performing particularly well last month, as did fragrances."
He added: "The two months leading up to Christmas account for a fifth of annual retail spending and these figures provide grounds for optimism for the rest of this crucial trading period."
Craig Cavin, head of retail in Scotland at KPMG, added: "Online is the new black in 2016 as cyber sales drove much of the growth while stealing the show on Black Friday.
"This may well herald the tone of years to come, with increasingly sophisticated online sales technology giving consumers a convenient yet rich shopping experience without the hassle of crowds."
Retail sales in Scotland have grown in real terms for a third month in a row, according to a report.