The United States is withdrawing from the UN Human Rights Council, the US ambassador to the world body said, calling it "an organisation that is not worthy of its name".
Ms Haley is President Donald Trump's envoy to the United Nations.
She said a year ago she made clear the US would stay in the council only if "essential reforms were achieved".
She said it was clear those calls for change were not heeded.
Ms Haley is decrying the membership of countries like China, Cuba and Venezuela that are themselves accused of rights violations.
She says the council also has a "chronic bias against Israel".
But Ms Haley says that if the council does reform, the United States "would be happy to rejoin".
Ms Haley announced the withdrawal at the State Department alongside US secretary of state Mike Pompeo.