Banks close 40% of Scottish branches in less than 5 years
The 38% reduction in branches reflects an "alarming rate'' of closures, the consumer organisation said, warning many Scots are struggling to access their banks.
Scotland has lost more than a third of its bank branches since 2015, according to new research.
Which? found banks shut 396 Scottish branches between January 2015 and August 2019, reducing the number from 1,039 to 643.
The 38% reduction in branches reflects an "alarming rate'' of closures, the consumer organisation said, warning many Scots are struggling to access their banks.
RBS was found to have closed the highest number of Scottish branches, with 158 branches - 63% of its total number - shutting during the past four-and-a-half years.
It was followed by Bank of Scotland, which closed 94 branches (32%).
Clydesdale shut 59 branches (47%), TSB closed 39 (21%) and 36 Santander branches were lost (44%).
The most affected areas, by Westminster constituency, were Edinburgh East, which lost 11 branches, equivalent to almost two-thirds (61%) of its network, with Moray losing 16 (59%), Edinburgh South West and Paisley & Renfrewshire North, which both lost eight branches (57%) and then Linlithgow and East Falkirk, which lost nine branches (56%).
The closures come amid a rise in online banking. But with an estimated 30% of people not using online services, Which? said banks should ensure those who rely on face-to-face banking are able to access it.
Money editor at Which?, Jenny Ross, said: "Banks are closing their branches at an alarming rate in Scotland, which risks shutting many people out of vital financial services and their ability to access their own cash.
"Bank branches play a crucial role within communities - serving consumers and businesses alike.
"The industry must ensure no-one is left behind by the digital transition and that when banks shut their doors they don't shut their customers out of important banking services.''
The research also looked at opening hours at the branches that have remained open and found "severely curtailed opening times''.
Of the remaining branches, 11 open just one day a week, while 31 are open for just two.
Overall, 14% (87 branches) open three days a week or less.
Public Finance Minister Kate Forbes said: "This new analysis is deeply concerning.
"Not only are branches closing at an alarming rate across Scotland but bank opening times are also reducing.
"Banks must take into account the needs of all customers, that is why we will continue to press regulators, banking providers and the UK Government to ensure that local banking services, and in particular access to cash services, remain accessible to all."