The National Organization for Women, which is connected to a PAC that endorsed the Biden-Harris ticket, said Barrett "will turn back the clock on equality."
"Donald Trump and the Senate Republicans want to steal another seat on the Supreme Court so that Amy Coney Barrett can help repeal Roe [v. Wade] and shred the Affordable Care Act – but not before she votes with a new, ultra-conservative majority to validate an election he intends to steal," the National Organization for Women said in a statement.
The president of Planned Parenthood Action Fund, the political arm of the organization, said nominating Barrett constituted a "particular insult to the legacy of Justice [Ruth Bader] Ginsburg."
"Barrett's history of hostility toward reproductive health and rights, expanded health care access, and more demonstrate that she will put Justice Ginsburg's long record of ensuring that everyone receives equal justice under the law at risk," Planned Parenthood President Alexis McGill Johnson said in a statement.
"Planned Parenthood Action Fund will rise up and fight to stop Amy Coney Barrett, and any nomination, before the 2021 Inauguration," she continued.
Planned Parenthood provides patients access to reproductive health services, including birth control and abortions.
EMILY's List, a PAC that supports Democratic women running for office on pro-choice platforms, and NARAL, another pro-choice group, also warned that Barrett is a "clear and present threat to reproductive freedom and the promise of Roe [v. Wade]," according to NARAL.
"President Trump and his Republican allies have made clear that they want the Supreme Court to overturn Roe v. Wade, and strike down the Affordable Care Act and many crucial civil rights. By nominating Judge Amy Coney Barrett, they will move one step closer to meeting those goals, and one step further away from voters," Emily's List said in a statement.
Meanwhile, six women who studied under Barrett at Notre Dame Law School praised their professor in a USA Today op-ed published on Sunday.
"We all have had the privilege of being Judge Barrett’s students," they wrote. "While we hold a variety of views regarding how best to interpret statutes and the Constitution, we all agree on this: The nation could not ask for a more qualified candidate than the professor we have come to know and revere."