A repertory theatre (also called repertory, rep or stock) can be a Western theatre and opera production in which a resident company presents works from a specified repertoire, usually in alternation or rotation. In the British system, however, it used to be that even quite small towns would support a rep, and the resident company would present a different play every week, either a revival from the full range of classics or, if given the chance, a new play, once the rights had been released after a West End or Broadway run. The companies were not known for trying out untried new work, however. The methods, now seldom seen, would be also used in the United States, Canada, and Australia.

The American Repertory Theater (A.R.T.) is a professional not-for-profit theatre in Cambridge, Massachusetts. Founded in 1980 by Robert Brustein, the A.R.T. is known for its commitment to new American plays and music–theater explorations; to neglected works of the past; and to established classical texts reinterpreted in refreshing new ways. Over the past thirty years it has garnered many of the nation's most distinguished awards, including a Pulitzer Prize (1982), a Tony Award (1986), and a Jujamcyn Award (1985). In December 2002, the A.R.T. was the recipient of the National Theatre Conference's Outstanding Achievement Award, and in May 2003 it was named one of the top three theaters in the country by Time Magazine. The A.R.T. is housed in the Loeb Drama Center at Harvard University.

In 2002 Robert Woodruff replaced founder Robert Brustein as the A.R.T.'s Artistic Director. After Woodruff's departure in 2007, Associate Artistic Director Gideon Lester took the reins for 2008-09 season, and in May 2008 Diane Paulus was named the new Artistic Director. Paulus, a Harvard alum, is widely known as a director of theater and opera. Her work includes The Donkey Show, which ran off-Broadway for six years; productions at the Chicago Opera Theatre; and the Public Theater's 2008 production of Hair, which won the Tony Award for Best Revival of a Musical.

Diane Paulus (born 1966 in New York City, USA) is an American director of theater and opera who became Artistic Director of the American Repertory Theater (ART) at Harvard University in 2009. Paulus was nominated for the Best Director Tony Award for her revival of Hair. She has received the 2009 Harvard College Women’s Leadership Award and the Columbia University IAL Diamond Award.

Paulus attended the Brearley School, studied dance at New York City Ballet and trained in classical piano. In 1988, she graduated magna cum laude from Harvard University with a Bachelor's degree in Social Studies and as a member of Phi Beta Kappa. She earned a Master's degree from the Columbia University School of the Arts.

Paulus and her husband, Randy Weiner, along with a few other theater school graduates established a small theater troupe in New York City called Project 400 Theatre Group. With Project 400, Paulus and Weiner specialized in creating avante-garde musical productions which married classic theater and modern music. Paulus' first production with the group was a rock version of The Tempest. Other productions included an R&B Phaedra and a hip-hop Lohengrin.