White House spokeswoman Anna Kelly said UNESCO "supports woke, divisive cultural and social causes that are totally out-of-step with the commonsense policies that Americans voted for."
The State Department accused UNESCO of supporting "a globalist, ideological agenda for international development at odds with our America First foreign policy".
It said its decision to admit the Palestinians as a member state was "highly problematic, contrary to U.S. policy, and contributed to the proliferation of anti-Israel rhetoric."
UNESCO chief Audrey Azoulay said she deeply regretted Trump's decision, but it was "expected, and UNESCO has prepared for it."
Posting on X, French President Emmanuel Macron professed "unwavering support" for the "universal protector" of world heritage and said the U.S. move would not weaken France's commitment to UNESCO.
UNESCO officials said the U.S. withdrawal would have some limited impact on U.S.-financed programs.
Azoulay said UNESCO had diversified funding sources, receiving only about 8% of its budget from Washington.
UNESCO was one of several international bodies Trump withdrew from during his first term, along with the World Health Organization, the Paris Agreement climate change accord, and the U.N. Human Rights Council. During his second term, he has largely reinstated those steps.
Trump's pick to be his U.N. envoy, Mike Waltz, said this month the United Nations needs reform while expressing confidence that "we can make the U.N. great again."
Israel welcomed the U.S. decision with its U.N. ambassador, Danny Danon, accusing UNESCO of "consistent misguided anti-Israel bias." In a post on X, Israel's Foreign Minister Gideon Sa'ar, thanked Washington for its "moral support and leadership" and said that "Singling out Israel and politicization by member states must end, in this and all professional UN agencies."
U.S. Senator Jeanne Shaheen, the senior Democrat on the Republican-controlled Senate Foreign Relations Committee, called Trump's decision "short-sighted and a win for China," which she said became the largest financial contributor to UNESCO after Trump last withdrew from the agency.
UNESCO officials said all relevant agency statements had been agreed with both Israel and the Palestinians over the past eight years.
Azoulay said the U.S. had given the same reasons for its pullout as it had seven years ago "even though the situation has changed profoundly, political tensions have receded, and UNESCO today constitutes a rare forum for consensus on concrete and action-oriented multilateralism."
"These claims also contradict the reality of UNESCO's efforts, particularly in the field of Holocaust education and the fight against antisemitism," she added.
The United Nations Educational, Scientific and Cultural Organization is best known for designating World Heritage Sites, including the U.S. Grand Canyon and Egypt's pyramids.
It lists 26 sites in the United States, including the Statue of Liberty, on its World Heritage List, opens new tab which highlights 1,248 global locations of "outstanding universal value."
