Fawn McKay Brodie (September 15, 1915 – January 10, 1981) was a biographer and professor of history at UCLA, best known for Thomas Jefferson: An Intimate History, a work of psychobiography, and No Man Knows My History, the first prominent non-hagiographic biography of Joseph Smith, Jr., the founder of the Latter Day Saint movement.

Raised in Utah in a respected, if impoverished, Latter-day Saint (LDS) family, Fawn McKay drifted away from religion during her years of graduate work at the University of Chicago and married the ethnically Jewish national defense expert Bernard Brodie, with whom she had three children. Although Fawn Brodie eventually became one of the first tenured female professors of history at UCLA, she is best known for her five biographies, four of which aim to incorporate the alleged insights of Freudian psychology.

Brodie's controversial depiction of Joseph Smith as a fraudulent "genius of improvisation" has been described as a "beautifully written biography ... the work of a mature scholar [that] represented the first genuine effort to come to grips with the contradictory evidence about Smith's early life." Her psychobiography of Thomas Jefferson became a best-seller and reintroduced Jefferson's slave and purported mistress Sally Hemings to popular consciousness even before advances in DNA testing increased evidence of a sexual liaison. Nevertheless, Brodie's study of Richard Nixon's early career, completed while she was dying of cancer, demonstrated the hazards of psychobiography in the hands of an author who loathed her subject.