Friedan died at her home of congestive heart failure, according to a cousin, Emily Bazelon.
Friedan's assertion in her 1963 best seller that having a husband and babies was not everything and that women should aspire to separate identities as individuals, was highly unusual, if not revolutionary, just after the baby and suburban booms of the Eisenhower era.
The feminine mystique, she said, was a phony bill of goods society sold to women that left them unfulfilled, suffering from "the problem that has no name" and seeking a solution in tranquilizers and psychoanalysis.
"A woman has got to be able to say, and not feel guilty, `Who am I, and what do I want out of life?' She mustn't feel selfish and neurotic if she wants goals of her own, outside of husband and children," Friedan said.
In the racial, political and sexual conflicts of the 1960s and '70s, Friedan's was one of the most commanding voices and recognizable presences in the women's movement.
As a founder and first president of the National Organization for Women in 1966, she staked out positions that seemed extreme at the time on such issues as abortion, sex-neutral help-wanted ads, equal pay, promotion opportunities and maternity leave.
But at the same time, Friedan insisted that the women's movement had to remain in the American mainstream, that men had to be accepted as allies and that the family should not be rejected.
"Don't get into the bra-burning, anti-man, politics-of-orgasm school," Friedan told a college audience in 1970.
To more radical and lesbian feminists, Friedan was "hopelessly bourgeois," Susan Brownmiller wrote at the time.
Friedan, deeply opposed to "equating feminism with lesbianism," conceded later that she had been "very square" and uncomfortable about homosexuality.
"I wrote a whole book objecting to the definition of women only in sexual relation to men. I would not exchange that for a definition of women only in sexual relation to women," she said.
Nonetheless she was a seconder for a resolution on protecting lesbian rights at the National Women's Conference in Houston in 1977.
"For a great many women, choosing motherhood makes motherhood itself a liberating choice," she told an interviewer two decades later. But she added that this should not be a reason for conflict with "other feminists who are maybe more austere, or choose to seek their partners among other women."