Joseph Kosuth (born January 31, 1945) is an influential American conceptual artist.

His work generally strives to explore the nature of art, focusing on ideas at the fringe of art rather than on producing art per se. Thus his art is very self-referential, and a typical statement of his goes:

"The 'value' of particular artists after Duchamp can be weighed according to how much they questioned the nature of art." Frames. 1965

One of his most famous works is "One and Three Chairs", a visual expression of Plato's concept of The Forms. The piece features a physical chair, a photograph of that chair, and the text of a dictionary definition of the word chair. All three representations are merely physical abstractions of the one true idea of the chair, thus the piece is both the three physical representations of a chair, and the one universal notion of a chair.

In an addition to his artwork, he has written several books on the nature of art and artists, including Artist as Anthropologist.

In Figeac, Lot, France, on the "Place des écritures" (writings place) is a giant copy of the Rosetta stone, by Joseph Kosuth.