Marcia Carolyn "Marcy" Kaptur (born June 17, 1946) is a Democratic Member of Congress from Ohio's Ninth Congressional District. She is currently the longest-serving woman in the House; in the Congress, she and Barbara Boxer are second after Barbara Mikulski.

Serving her fourteenth term, she ranks 30th out of 435 members in seniority and serves on the powerful Appropriations Committee.

Kaptur, a Polish-American, is a Toledo native. Her family operated a small grocery. Kaptur graduated from St. Ursula Academy in 1964 and became the first member in her family to attend college. She received her undergraduate degree from the University of Wisconsin-Madison in 1968 and a master's in urban planning from the University of Michigan in 1974. She did post-graduate study in urban planning at the Massachusetts Institute of Technology in 1981.