Vito Acconci (Italian: [ˈviːto akˈkontʃi], /əˈkɒntʃi/; January 24, 1940 – April 27, 2017) was an American performance, video and installation artist, whose diverse practice eventually included sculpture, architectural design, and landscape design. His performance and video art was characterized by "existential unease," exhibitionism, discomfort, transgression and provocation, as well as wit and audacity, and often involved crossing boundaries such as public–private, consensual–nonconsensual, and real world–art world. His work is considered to have influenced artists including Laurie Anderson, Karen Finley, Bruce Nauman, and Tracey Emin, among others.

Acconci was initially interested in radical poetry, creating 0 to 9 Magazine, but by the late 1960s he began creating Situationist-influenced performances in the street or for small audiences that explored the body and public space. Two of his most famous pieces were Following Piece (1969), in which he selected random passersby on New York City streets and followed them for as long as he was able, and Seedbed (1972), in which he claimed that he masturbated while under a temporary floor at the Sonnabend Gallery, as visitors walked above and heard him speaking.

In the late-1970s, he turned to sculpture, architecture and design, greatly increasing the scale of his work, if not his art world profile. Over the next two decades he developed public artworks and parks, airport rest areas, artificial islands and other architectural projects that frequently embraced participation, change and playfulness. Notable works of this period include: Personal Island, designed for Zwolle, the Netherlands (1994); Walkways Through the Wall at the Wisconsin Center, in Milwaukee, WI (1998); and Murinsel, for Graz, Austria (2003). Retrospectives of Acconci's work have been organized by the Stedelijk Museum in Amsterdam (1978) and the Museum of Contemporary Art, Chicago (1980), and his work is in numerous public collections, including those of the Museum of Modern Art and Whitney Museum of American Art. He has been recognized with fellowships from the National Endowment for the Arts (1976, 1980, 1983, 1993), John Simon Guggenheim Memorial Foundation (1979), and American Academy in Rome (1986). In addition to his art and design work, Acconci taught at many higher learning institutions. Acconci died on April 28, 2017, in Manhattan at age 77.

Acconci was born Vito Hannibal Acconci in the Bronx, New York, in 1940. After attending a Roman Catholic elementary school, he attended Regis High School in Manhattan. He then graduated from the College of the Holy Cross in Worcester, Massachusetts, with a Bachelor of Arts with honors in English literature in 1962. As an undergraduate at Holy Cross, Acconci was co-editor of the college's literary magazine, The Purple. He then earned a Master of Fine Arts in literature and poetry from the University of Iowa. He later recalled: "There wasn't a woman in my classroom between kindergarten and graduate school." Then he returned to New York City to pursue a career as a poet.

Acconci began his career as a poet, editing and self-publishing the poetry magazine 0 TO 9 with Bernadette Mayer in the late 1960s. Produced in quantities of 100 to 350 copies per issue on a mimeograph machine, the magazine mixed contributions by both poets and artists.

In the late 1960s, Acconci transformed himself into a performance and video artist using his own body as a subject for photography, film, video, and performance. Most of his early work incorporated subversive social comment. His performance and video work was marked heavily by confrontation and Situationism. In the mid-1970s, Acconci expanded his métier into the world of audio/visual installations. The Museum of Modern Art describes Following Piece as a work in which Acconci randomly selected individual passersby in New York City and followed them until they entered a building.

One installation/performance work from this period, perhaps his best known work, is Seedbed (January 15–29, 1972). In Seedbed Acconci lay hidden underneath a gallery-wide ramp installed at the Sonnabend Gallery, masturbating while vocalizing into a loudspeaker his fantasies about the visitors walking above him on the ramp. One motivation behind Seedbed was to involve the public in the work's production by creating a situation of reciprocal interchange between artist and viewer.

His 1969 work Following Piece involved him following random pedestrians in New York City until they entered a building.