Fantifa (sometimes rendered as f_antifa or f*antifa; a contraction of German Feministische Antifa, lit. feminist anti-fascism, or Frauen Antifa, lit. women's anti-fascism) is an umbrella term for anti-fascism movements centering on women as a branch of the feminist movement. The term mostly refers to a formal movement of feminist anti-fascist groups that emerged from German-speaking countries in 1985 but also encompasses historical German groups such as the 1925 Rote Frauen und Mädelbund (the women and girls' branch of the Roter Frontkämpferbund) and broader European groups such as the 1930s Spanish anarcha-feminist group Mujeres Libres, the 1934 French women's branch of the World Committee Against War and Fascism, and the 1942 Yugoslavian partisan group Women's Antifascist Front of Yugoslavia. The main fantifa movement holds an anarcho-communist philosophy and is specifically an anti-fascist variant of anarcha-feminism, as is sometimes represented in the use of a purple and black flag with a symbol derivative of that of the men's antifa group Antifaschistische Aktion.

Fantifa has its roots in the West German antifa movement and in anti-fascist sentiments of German second-wave feminist groups such as Rote Zora, which emphasized anarchist defiance through terrorist action. In 1980, Rote Zora issued a statement urging feminists to take action against every form of oppression, including that imposed by the state. Concerns of theirs included genetic engineering as a form of eugenics and § 218 of the German Penal Law limiting abortion. 1980s Black and Jewish feminist criticism of Rote Zora in displaying aspects of white feminism coincided with women's resentment toward machismo in the antifa movement and led to the creation of fantifa, beginning with a Northern Germany women's antifa meeting in 1985. As it came as a response to restrictive second-wave feminist politics and extended into the 1990s, this era of fantifa can be classified as third-wave feminism.

The term "fantifa" was coined in 1988, with small meetings of no more than fifteen people occurring in 1989, which covered topics including violence against women. Following the fall of the Berlin Wall, the first nationwide German fantifa meeting was held on the weekend of January 20-21, 1990, covering the topics of lesbophobia, eugenics, anti-abortion movements, and § 218. It was the first antifa meeting to feature daycare, to allow women with children to participate. By the end of the 1990s, there were twenty-five fantifa groups.

Fantifa initially met with conflict from antifa men who viewed women's rights groups as fascist, perceiving feminism's antagonism toward patriarchy as misandry equivalent to antisemitic hatred. Further confusion was caused by the historical example of fascist woman Sophie Rogge-Börner writing to Adolf Hitler in 1933 to preach for uplifting women who wished to take on more traditionally masculine gender roles within the Nazi movement, but she distanced herself from feminism and fantifa activists did not consider her one either, merely a fascist seeking an androgyny within patriarchy. In the mid-1990s, a Hamburg men's antifa group accepted fantifa and promoted feminist talking points within the context of antifa academic discourse, as did a 1998 Berlin leftist newspaper. However, very few men showed up in solidarity at 1990s fantifa protests.

Internal discord over how to handle the intersection of racism and sexism and if fantifa's primary focus should be lesbian rights threatened to fracture the movement early on but antisemitic violence in 1992 brought the movement together with a common enemy: neo-Nazism, manifesting in groups like the Free German Workers' Party. Like in the main German antifa movement, neo-Nazi antisemitic violence throughout the 1990s emboldened fantifa in response. 1990s fantifa feminist activism included anti-pornography efforts, distributing flyers to advocate for closing down sex shops and encouraging men not to view pornography, as well as protesting anti-abortion movements, supporting the anti-nuclear movement, and demonstrating on International Women's Day.

Another nationwide Germany fantifa meeting was held in Berlin in 1999, but the movement lost momentum after that. In 2000, a fantifa member accused an antifa man of raping her in 1998. The resulting fallout caused a divide in men's antifa groups, either choosing to embrace feminism as a worthy cause or deny it as relevant to anti-fascism. Fantifa dwindled after that for a variety of reasons; however, it saw a resurgence in the 2010s.

The general German antifa movement fractured in 2001, splintering off into competing anti-nationalist groups. Following the September 11 attacks, far-left movements increasingly turned their aggression toward other leftist movements instead of viewing the threat of neo-Nazism as important enough to actively target. Antifa groups lost their perceived relevancy, and fantifa likewise diminished into obscurity.

Simultaneously, the fantifa of the 1990s could not continue in its same form very far into the 2000s due to the changing nature of feminism. The influence of Judith Butler disrupted the radical feminist politics of German feminism. When fantifa was revived, feminism was transitioning from its third wave to its fourth and fantifa incorporated queer feminist ideology as part of this shift.