Marieluise Fleißer (German: [maˌʁiːluˈiːzə ˈflaɪsɐ]; 23 November 1901, Ingolstadt – 2 February 1974, Ingolstadt) was a German author and playwright.

Fleißer's best-known works are two plays, Purgatory in Ingolstadt (1924) and Pioneers in Ingolstadt (1928). The plays, which feature lower-class characters from small town Bavaria, deal with abusive, sometimes violent relationships between men and women. Among literary scholars, the plays are categorized as "critical Volksstücke," a genre that references and engages critically with the conventions of the popular "Volksstück" (literally people's play, also "milieu plays"). Like the original "Volksstück," Fleißer's dramas feature regional (Bavarian) dialect, lower-class characters, and deal with everyday themes and relationships, but unlike the originals, Fleißer exposes unequal power relationships between men and women.

Bertolt Brecht persuaded the director Moriz Seeler to stage the first play, which Seeler retitled; Fleißer's original title was The Washing of Feet. Brecht then encouraged her to write Pioneers. Premiered in Berlin, the plays caused a scandal, especially in her home town, and were attacked by the Nazis, who had not yet come to power.

Fleißer was rediscovered in the 1970s by a later generation, among them the theatre director Peter Stein and the playwright Franz Xaver Kroetz. Pioneers in Ingolstadt was adapted as a TV film by Rainer Werner Fassbinder in 1971.

The plays were given their London premieres at the Gate Theatre, London, in 1990, directed by Annie Castledine and Stephen Daldry.