Everett Irwin Mendelsohn (October 28, 1931 – June 6, 2023) was an American historian of science, particularly active in the history of biology.

He was Professor Emeritus of the History of Science at Harvard University, where he was a Junior Fellow and then a faculty member from 1960 until his retirement in 2007.

A self-described pacifist, he was active in attempting to negotiate peace in the Middle East both as the chair of the American Academy of Arts and Sciences' Committee on Middle East Studies and through his work with the American Friends Service Committee.

[9] He received the Gregor Mendel Medal from the Czechoslovak Academy of Sciences in 1991 and the Phi Beta Kappa Teaching Prize in 1996.

[10] In 2007, when Mendelsohn announced his impending retirement, his Harvard colleague Anne Harrington described him as "one of the founders of the social history of science.