Wearing safety goggles and Kevlar gloves, Extinction Rebellion protesters broke the glass of the bank’s Clyde Place Quay branch ahead of a demonstration outside the company’s outlet later on Monday.
Police Scotland said two men had been arrested, and investigations were ongoing.
Images released by the campaign groups show the window panes of the building at its multi-million pound Glasgow campus broken as three protesters held up banners declaring “this is an intervention” amid calls for the company to “stop funding Rosebank”.
Rosebank is an oil and gas field around 100 miles off the coast of the Shetland Island that First Minister Nicola Sturgeon was urged to help bring to a halt after she was approached by a climate protester at COP27 in Sharm El-Sheikh last week.
The Glasgow protesters said the field had more than 500 million barrels of oil, and claim Barclays have provided Norwegian state-owned firm Equinor with $2.46 billion of backing since 2015.
In footage released by the group, police liaison officers can be seen at the bank with police vans and cars arriving as they held their banners.
One Extinction Rebellion protester said they were taking the action because “Barclays are finding the destruction of our planet, and they are funding the destruction of our children’s future”.
“I cannot stand by and do nothing while Barclays fund the collapse of society,” she said.
Alex Cochrane, of Extinction Rebellion Scotland, said the bank was the “biggest funders of fossil fuel in Europe”.
“Their greed is exploiting and creating a future of famine, displaced people and global suffering,” he said.
“We all know we need to wean ourselves off fossil fuels. We all know the climate crisis is already hitting us yet Barclays still refuses to do the right thing for us.
“For all our sakes, they must stop using our money to fund fossil fuels.”
The group claimed the action in Scotland’s biggest city followed in the footsteps of suffragettes and the Ploughshares movement, “using nonviolent direct action and causing damage to property to prevent and draw attention to greater damage”.
A Police Scotland spokesman said: “Around 8:10am on Monday, November 14, police were made aware of damage to a property in Kingston Street, Glasgow. Officers attended and two men have been arrested. Inquires are ongoing.”
Barclays has been approached for comment.