Anti-art is a loosely-used term applied to an array of concepts and attitudes that reject prior definitions of art and question art in general. Anti-art tends to conduct this questioning and rejection from the vantage point of art. The term is associated with the Dada movement and is generally accepted as attributable to Marcel Duchamp pre-World War I, when he began to use found objects as art.

An expression of anti-art can take the form of art or not. In general, anti-art rejects only some aspects of art. Depending on the case, "anti-artworks" may reject conventional artistic standards.

Anti-artworks may also reject the art market, and high art. Anti-artworks may reject individualism in art. Anti-art may reject "universality" as an accepted factor in art, and some forms of anti-art reject art entirely. Depending on the case, anti-art artworks may reject art as a separate realm or as a specialization

Anti-art artworks may reject art based upon a consideration of art as being oppressive of a segment of the population.

Anti-art artworks may articulate a disagreement with the generally supposed notion of there being a separation between art and life. Indeed, anti-art artworks may voice a question as to whether "art" really exists or not. "Anti-art" has been referred to as a "paradoxical neologism," in that its ostensible opposition to art has been observed concurring with staples of twentieth century art or "modern art," in particular art movements that have self-consciously sought to transgress traditions or institutions. Anti-art itself is not a distinct art movement, however. This would tend to be indicated by the time it spans—longer than that usually spanned by art movements. Some art movements though, are labeled "anti-art." The Dada movement is generally considered the first anti-art movement; the term anti-art itself is said to have been coined by Dadaist Marcel Duchamp around 1914, and his ready-mades have been cited as early examples of anti-art objects. Theodor W. Adorno in Aesthetic Theory (1970) stated that "...even the abolition of art is respectful of art because it takes the truth claim of art seriously."

Anti-art has become generally accepted by the artworld to be art, although some people still reject Duchamp's readymades as art, for instance the Stuckist group of artists. who are "anti-anti-art".