They get eight public holidays a year, which is four fewer than the EU average and half the number in Japan.
The umbrella body for unions, the TUC, is calling for a new public holiday between September and Christmas.
It would be "a great way to thank working Britain for getting us through these tough times," TUC general secretary Frances O'Grady said.
"The August Bank Holiday will be a welcome break for everyone working hard to get us through the pandemic - especially those on the front line," said Ms O'Grady.
"But after August, there's no national holiday until Christmas. And that's because the number of holidays we get is so stingy compared to other nations."
Even in Scotland, with nine bank holidays, and Northern Ireland which has 10 public holidays, the situation is only slightly better.
A spokesman for the Department for Business, Energy & Industrial Strategy said: "The current pattern of public and bank holidays is well established and whilst an additional bank holiday may benefit some communities and sectors, the cost to the economy of an additional bank holiday is considerable."
According to the TUC every EU-member is more generous than the UK when it comes to public holidays.
Several countries including Romania, Slovakia, Slovenia and Finland give 15 days off. The EU average is 12.8 days a year, the TUC said.
Japan's workers enjoy 17 days off a year but New Zealanders only get 11.
However, in many countries if a bank holiday falls at the weekend, workers are not entitled to an additional day off. So in practice workers don't always enjoy as many holidays as the officially listed days suggest.
The TUC says all UK workers should get at least 12 public holidays and is calling for a wider debate on the issue.
"It's time for a national conversation - when should our new holidays be? What might they celebrate?" added Ms O'Grady.
"An autumn holiday to break the long stretch to Christmas would be a good start."
Those who have to work on bank holidays are entitled to be paid a premium or receive time off in lieu, the TUC said.
Bank holidays are created under the Banking and Financial Dealings Act 1971, or are created by royal proclamation - that is, by the Queen, who acts on government advice.
The department responsible for bank holidays is the Department of Business, Energy and Industrial Strategy.
Bank holidays are not actually statutory holidays, although most workers do get the day off.