“New” is indisputably the operative adjective at Signature Theatre next season. The Arlington-based company, which won the 2009 Tony Award for outstanding regional theater, will stage five world premieres in 2011-12, including an unprecedented four original musicals.

Putting on musicals that it has developed itself is a riskier business for a small company, one without the deep pockets of an institution such as Lincoln Center or the Kennedy Center. But the potential rewards are also greater, in terms of organizational prestige and, in even rarer cases, long-range financial return.

Eric Schaeffer, the company’s longtime artistic director, is hoping that this batch of new work will include some breakout material, a result that by and large has eluded Signature in the past. “It’s like no one else is going to do this — in their right mind, I think,” he said, laughing.

As if to underline the nerviness of the offerings, Signature will introduce two of them at the start of the season by running them in revolving repertory. In August, “The Hollow,” by composer-lyricist Matt Conner and book writer Hunter Foster, based on Washington Irving’s “The Legend of Sleepy Hollow,” will begin alternating performances with “The Boy Detective Fails,” adapted from Joe Meno’s novel by Meno and composer-lyricist Adam Gwon.

Schaeffer and Joe Calarco, the respective directors of “Hollow” and “Boy Detective,” will share resources on Signature’s main stage, the Max, including a single cast. The rollout of new musicals continues in November, with a weekend of performances of “A Second Chance,” a two-character show by Ted Shen, the New York philanthropist whose Shen Family Foundation has provided the money for several original musicals at Signature, including the current production, “And the Curtain Rises.”

The story of two New Yorkers who find love through a passion for art, “A Second Chance” will be directed by Jonathan Butterell, who in 2009 staged “Giant,” another Signature musical underwritten by the Shens’ grants.

February brings the last of the new musicals, John Dempsey and Dana Rowe’s “Brother Russia.” The songwriters, collaborators on Signature’s vivacious “The Witches of Eastwick” a few years back, this time build a show around a provincial Russian theater troupe and its unlikely star: Rasputin. Schaeffer will direct.

A fifth world premiere is a play: Paul Downs Colaizzo’s “Really Really,” a drama directed by Matthew Gardiner that takes as its subject the repercussions a calamitous event at a party at a top-rank college. Among other productions will be limited runs of Stephen Sondheim’s early, rarely revived musical, “Saturday Night,” and E. Patrick Johnson’s one-man show, “Sweet Tea: Black Gay Men of the South.”

In addition, the Washington region’s premieres of Yasmina Reza’s yuppie-couple comedy, “God of Carnage,” and the parody musical “Xanadu,” based on a loopy 1980 movie starring Olivia Newton-John, will bring local versions of two successful Broadway works of recent vintage to the company’s stages.

And Signature is hoping to raise holiday spirits with the most familiar title on its 2011-12 agenda: “Hairspray,” to be staged by Schaeffer and filling the lucrative slot from Thanksgiving into the new year.