The left-leaning 83-year-old judge shocked the US political establishment with her remarks: on Monday she called Trump "a faker" who "says whatever comes into his head at the moment."
She also told The New York Times in an interview published last weekend that she "can't imagine" what the United States under Trump as president would be like.
Ginsburg issued a statement today saying she was sorry.
"On reflection, my recent remarks in response to press inquiries were ill-advised and I regret making them," Ginsburg said.
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In response to the criticism, Trump had suggested the judge was getting senile and should step down.
"Justice Ginsburg of the US Supreme Court has embarrassed all by making very dumb political statements about me. Her mind is shot - resign!" he tweeted yesterday.
Ginsburg drew widespread ire from Republicans for breaking with a code of conduct under which US judges are not supposed to publicly endorse or oppose a candidate for office.
The Washington Post and The New York Times both ran editorials saying she had erred.
She has lots of clout. Last year, she was named to Time's list of the 100 Most Influential People in the world.
As a lawyer, Ginsburg was a pillar of the fight for women's rights in the 1960s and '70s. She has survived cancer several times.
But her departure from judicial custom in slamming Trump raised eyebrows everywhere, even among ideological allies.
The Washington Post, which rarely goes easy on Trump, said in an editorial that while it may agree with what Ginsburg said about him, her candor was "inconsistent with her function in our democratic system."