The Redbrae Pub, in the East Dunbartonshire town, was set upon at around 1.45am on Sunday morning.
Fire crews and police were called after locals spotted flames coming from the boozer.
They arrived at the scene before 2am and didn’t leave until 11am.
Nobody was injured in the blaze.
Locals claimed the pub had been petrol-bombed in in the early morning incident.
The inferno is being treated by police as ‘wilful’ and officers say enquiries are ongoing.
The devastated owners took to social media to tell punters that the boozer would be ‘closed until further notice’.
It had been shut down for months during the coronavirus lockdown.
The statement read: “Due to unforeseen circumstances the pub will be closed until further notice.
“If you have a booking, it will be cancelled, please accept our apologies in this matter.”
‘Gutted’ locals took to social media to express their sadness at the ‘absolutely shocking’ incident.
One reveller wrote: “Devastated for you guys.
“You have worked so hard to get to where you are today.
“Wish you all the best to get back on your feet.”
Another commented: “Absolutely gutted for you guys.
“So much hard work and effort put into opening back up.”
A third added: “Unbelievable, I’m so devastated for you guys after everything everyone has been though last few months and someone’s done this.”
A Police Scotland spokeswoman told the Record: “We were made aware of a fire at a pub on Redbrae Road, Kirkintilloch, around 1.45am on Sunday, August 2.
“Officers attended alongside the fire service.
“Nobody was injured.
“The fire is being treated as wilful and enquiries are ongoing.”
A Police Scotland spokesperson said: “We were made aware of a fire at a pub on Redbrae Road, Kirkintilloch, around 1.45am on Sunday, 2 August, 2020.
“Officers attended alongside the fire service. Nobody was injured. The fire is being treated as wilful and enquiries are ongoing.”
A spokesperson for the Scottish Fire and Rescue Service told the Record: “We were called to an incident at the Redbrae Pub in Kirkintilloch at 1.48 am on Sunday, August 2.
“Operations Control mobilised three appliances and crews left the scene at 11am.
“There were no casualties”.
It comes just weeks after First Minister Nicola Sturgeon announced that beer gardens were allowed to re-open for the first time since March.
A few weeks later, the Scottish Government permitted bars and restaurants to open their doors to customers who wished to sit inside.
Scotland’s hospitality sector was hit hard when the coronavirus pandemic put the country on lockdown on March 23.