US President Donald Trump criticized South Africa "a total disgrace" and said the US will not participate.
He made the announcement over claims that white people are being prosecuted in the country.
The G20 summit, which brings together leaders of the world's largest economies is scheduled to take place later this month in Johannesburg.
Trump posted on his social media platform Truth Social, stating, "It is a total disgrace that the G20 will be held in South Africa.
"Afrikaners (people who are descended from Dutch settlers, and also French and German immigrants) are being killed and slaughtered, and their land and farms are being illegally confiscated," he wrote.
The President added, "No US government official will attend as long as these human rights abuses continue."
South Africa's foreign ministry described the decision by the White House as "regrettable."
Each year a different country hosts the G20 summit, and sets the agenda for the summit.
Since returning to office in January, Trump has often claimed that South Africa treats its white population unfairly and he even mentioned this directly to South African President Cyril Ramaphosa during a meeting at the White House in May.
While, South African court had already declared earlier this year that the claim of white genocide was false and baseless.
