Roberta Ann Kaplan (born 1966) is an American lawyer focusing on commercial litigation and public interest matters. Kaplan successfully argued before the Supreme Court of the United States on behalf of LGBT rights activist Edith Windsor, in United States v. Windsor, a landmark decision that invalidated a section of the 1996 Defense of Marriage Act and required the federal government to recognize same-sex marriages. She was a partner at Paul, Weiss, Rifkind, Wharton & Garrison before starting her own firm in 2017. In 2018, she co-founded the Time's Up Legal Defense Fund.