Thunberg responded by changing her Twitter profile bio to read: “A teenager working on her anger management problem. Currently chilling and watching a good old fashioned movie with a friend.”
Mr Trump’s attack on the teenager comes a week after his wife, Melania Trump, after a professor made a joke during impeachment hearings about their son, Barron.
“A minor child deserves privacy and should be kept out of politics,” she said.
It’s not the first time Mr Trump has lashed out after not being recognised for his influence.
In 2015, Mr Trump attacked German Chancellor Angela Merkel for “ruining Germany” after she was named Person of the Year, when he was listed as a runner-up.
Mr Trump is the second world leader to take aim at Thunberg this week, after her concern over the slayings of indigenous Brazilians in the Amazon drew a harsh rebuke from the Latin American nation’s president.
“Greta said that the Indians died because they were defending the Amazon,” Jair Bolsonaro said. “It’s impressive that the press is giving space to a brat like that,” he added, using the Portuguese word for brat, aka “pirralha.”
Thunberg responded by changing her bio on Twitter, where she has over 3 million followers, to say “Pirralha.”