Joan Tower (born September 6, 1938) is a Grammy-winning contemporary American composer, concert pianist, and conductor. Her work has been performed worldwide. Since gaining recognition for her first orchestral composition, Sequoia (1981), a tone poem that structurally depicts a giant tree from trunk to needles, she has written a variety of instrumental works, including Fanfare for the Uncommon Woman—something of a response to Aaron Copland's Fanfare for the Common Man—the Island Prelude, five string quartets, and an assortment of other tone poems. Tower was the pianist and a founding member of the Naumburg Award-winning Da Capo Chamber Players, which commissioned and premiered many of her early works, including her widely performed Petroushskates. The New Yorker has called her "one of the most successful woman composers of all time".

Born in New Rochelle, New York, in 1938, Tower moved to Bolivia when she was nine years old, an experience she credits for making rhythm an integral part of her work. She discovered this love for rhythm in the local saint's day celebrations. There, she learned how to play percussion and then started her musical journey. For the next decade Tower's talent in music, particularly on the piano, grew rapidly due to her father's insistence that she benefit from consistent musical training. Tower's relationship with her mineralogist father is visible in many aspects of her work, most specifically her "mineral works", such as Black Topaz (1976) and Silver Ladders (1986). She returned to the United States as a young woman to study music, first at Bennington College and then at Columbia University, where she studied with Otto Luening, Jack Beeson, and Vladimir Ussachevsky and was awarded her doctorate in composition in 1968.

In 1969 Tower, violinist Joel Lester, and flutist Patricia Spencer founded the New York-based Da Capo Chamber Players, where she served as the group's pianist. During the late 1970s and early 1980s Tower wrote a number of works for the Da Capo Players, including Platinum Spirals (1976), Amazon I (1977), and Wings (1981). The group won several awards in its early years, including the Walter W. Naumburg International Competition Award in 1973. Tower left the group in 1984, buoyed by the immediate success of her first orchestral composition, Sequoia (1981). Tower also was influenced by jazz music, having seen performers such as Miles Davis and John Coltrane in New York City clubs. This inspired her to become a jazz pianist for ten years and implement jazz chords in many of her works.

In 1972 Tower had accepted a faculty position at Bard College in composition, a post she continues to hold today. She received a Guggenheim fellowship in 1976. From 1985 to 1988 Tower was composer-in-residence at the St. Louis Symphony Orchestra.

Tower became the first woman recipient of the Grawemeyer Award for Music in 1990 for Silver Ladders. In 1993, on a commission from the Milwaukee Ballet, Tower composed Stepping Stones, and she conducted sections from it at the White House. Other compositions from the 1990s include the third Fanfare for the Uncommon Woman, several piano concertos (notably 1996's Rapids (Piano Concerto no. 2) and Tambor (1998), written for the Pittsburgh Symphony Orchestra. In 1999 Tower accepted a position as composer-in-residence with the Orchestra of St. Luke's and in 1998 she won the Delaware Symphony's Alfred I. DuPont Award for Distinguished American Composer.

In 2002 Tower won the Annual Composer's Award from the Lancaster Symphony. During the 2003–04 season two new works were debuted, DNA, a percussion quintet commissioned for Frank Epstein, and Incandescent. In 2004 the Nashville Symphony's recording of Tambor, Made in America, and her Concerto for Orchestra earned a Grammy nomination. In 2004 Carnegie Hall's "Making Music" series featured a retrospective of Tower's body of work, performed by artists including the Tokyo String Quartet and pianists Melvin Chen and Ursula Oppens. In 2005 Tower became the first composer commissioned for the "Ford Made in America" program, the only project of its kind to involve smaller-budget orchestras as commissioning agents of new work by major composers, in which her 15-minute Made in America was performed in every state of the union during the 2005–2007 season. In 2008, Made in America and its recording by the Nashville Symphony conducted by Leonard Slatkin won three Grammy Awards: Best Orchestral Performance, Best Classical Album, and Best Classical Contemporary Composition.

Alongside those listed above, her work has been performed by many of the world's leading orchestras and chamber ensembles, including The Orchestra Now, the New York Philharmonic, the Boston Symphony Orchestra, Seraph Brass, and the American Brass Quintet.

Tower is the Asher B. Edelman Professor of Music at Bard College in Annandale-on-Hudson, New York, and a member of the American Academy of Arts and Letters. She also serves on the Artistic Advisory panel of the BMI Foundation.