Katherine Marlea Clark (born July 17, 1963) is an American lawyer and politician who has served as House Minority Whip since 2023 and the U.S. representative for Massachusetts's 5th congressional district since 2013.

[11] Festa resigned his state House seat in October 2007 to become secretary of elder affairs in the Deval Patrick administration, and Clark entered the special election to succeed him.

During the campaign, she emphasized her experience as an attorney and made "developing stability in state aid" her top policy issue.

[22][23][24] In 2011, Clark was co-chair of the Joint Committee on Public Service, where she was lead author of the Senate version of a bill to reform municipal pensions.

[29] Also in 2012, her bill extending restraining orders in domestic violence cases to cover victims' pets, which are often used as pawns in abusive relationships, was signed as part of a larger law on animal shelters.

[30][31] In 2013, she co-sponsored a bill expanding the state's wiretapping authority, which was strictly limited under existing law, in order to help police better investigate violent street crime.

In March 2015, Clark decided not to attend the speech by Israeli prime minister Benjamin Netanyahu before a joint session of Congress.

[57][58] Clark has introduced legislation in response to Internet harassment, most notably resulting from the Gamergate controversy, and has advocated for more stringent enforcement of existing laws.

"[62] Clark votes with President Joe Biden's stated position 100% of the time, according to FiveThirtyEight analysis completed in January 2023.

[63] On November 28, 2018, it was announced that Clark had defeated California congressman Pete Aguilar to succeed Linda Sánchez as vice chair of the House Democratic Caucus.

[64][65] On November 18, 2020, it was announced that Clark had defeated Rhode Island congressman David Cicilline by a vote of 135 to 92 to succeed Ben Ray Luján as assistant speaker, the number four spot in Democratic house leadership.

In January 2023, Clark confirmed that her adult daughter was arrested for assault by means of a dangerous weapon and damage to property by graffiti/tagging Boston Common's Parkman Bandstand with the words "NO COP CITY" and "ACAB".

[76] When Congress is in session, Clark rooms with Representatives Annie Kuster, Grace Meng, Lois Frankel, Cheri Bustos, and Julia Brownley.