Ruth Mazo Karras (born February 23, 1957) is an American historian and medievalist, whose academic research and publications are focused on the disciplines of sexuality, religion and marriage in the late Middle Ages.

[15][16] Since 2018, she has been the Lecky Professor of History at Trinity College Dublin, teaching courses on medieval sources, marriages, and Christianity and Judaism during the Middle Ages.

As primary sources, Karras employs court records, hagiography, prescriptive texts, administrative documents, and Icelandic sagas to inform her analysis.

[32][33][34][35] Karras has received praise for her innovative research approaches when considering medieval masculinities and analyzing the sexual unions of marriage and prostitution during the Middle Ages.

[36] Several other medieval scholars have praised Unmarriages for its fresh research complied with unpublished church court records and the intersectionality between legal, sexual and economic histories.

[39] Ruth Mazo Karras has received numerous awards and honors throughout her career, including: the Rhodes Scholarship from 1979-1981; the National Endowment for the Humanities grant in 1989; American Philosophical Society research grant in 1989; she was named Scholar of the College of Liberal Arts at the University of Minnesota, Minneapolis in 2003; she was accepted as a member of the Institute for Advanced Studies at Princeton University in 2003-2004; she received the Distinguished Women Scholars Award in Humanities, Social Sciences and Arts at the University of Minnesota, Minneapolis in 2008; she was honored with the Dean's Medal and Graduate-Professional Teaching Award at the University of Minnesota, Minneapolis in 2010; in 2012, she was honored as "Feminist Foremother" by the Society for Medieval Feminist Scholarship and the Joan Kelly Prize in Women's History from the American Historical Association for her work in Unmarriages; and she was an invited member to the Israel Institute for Advanced Study in 2016-2017.

[46][47] More recently, Karras was the North American Co-Editor for Gender and History from 2008-2013; President of the Berkshire Conference on the History of Women from 2005-2008; served on the Editorial Board for the American Historical Review; and the Medieval Academy of America Chair of the Ad Hoc Committee on Harassment in 2018, Second Vice-President from 2017-2018, First Vice-President from 2018-2019, and President from 2019-2020.