From next Wednesday, anyone found guilty of having gay sex or being an adulterer could be whipped or face the death penalty.
In 2014, Brunei became the first south-east Asian country to adopt Islamic Sharia law.
Mr Clooney said: “Every single time we stay at, or take meetings at, or dine at any of these nine hotels we are putting money directly into the pockets of men who choose to stone and whip to death their own citizens for being gay or accused of adultery.
“Are we really going to help fund the murder of innocent citizens?”
Through its sovereign wealth fund Brunei owns The Dorchester and 45 Park Lane in London, as well as Coworth Park in Berkshire.
The hotel group has been contacted for comment.
source: express.co.uk