The BBC are reporting that the former Florida governor made the surprise suggestion during a televised debate for the top Republicans vying for the presidential nomination.
All 11 candidates were asked who they would choose, now the US Treasury has announced plans to put a woman on the redesigned note.
Mr Bush’s choice drew applause.
“I would go with Ronald Reagan’s partner, Margaret Thatcher,” he said, noting it was “probably illegal” and unlikely to happen because she is not American.
But he added: “A strong leader is what we need in the White House, and she certainly was a strong leader that restored the United Kingdom into greatness.”
He was not the only Republican to pick a foreigner to grace the new note, which comes into circulation in 2020.
Mother Teresa was the choice of the Governor of Ohio, John Kasich.
Two candidates picked civil rights heroine Rosa Parks, while rising star Carly Fiorina dismissed the question as gesture politics.
